Copyright © 2020 Cellcrypt Limited. All rights reserved.
The information contained in this document, including all ideas and technologies described herein, is proprietary
to Cellcrypt. Neither the whole nor any part of the information contained in this document may be adapted or
reproduced in any material or electronic form without the prior written consent of the copyright holder.
Security Target
Cellcrypt Server
Ref: ST-FED-SRV-1
Ver: 1.0.0
Date: June 10, 2022
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 2 of 76
Contents
1. Introduction.................................................................................................................... 8
1.1. ST and TOE Reference .......................................................................................... 8
1.2. Overview................................................................................................................. 8
1.3. Description.............................................................................................................. 8
1.3.1. Physical Scope of the TOE........................................................................... 8
1.3.2. Logical Scope of the TOE............................................................................. 9
1.3.3. TOE Logical Architecture............................................................................ 11
1.3.4. Network Services ....................................................................................... 12
1.3.5. Network Deployment Diagram.................................................................... 15
1.3.6. List of Secure Communications Ports......................................................... 15
1.3.7. TOE operational components..................................................................... 16
1.3.8. TOE Exclusions.......................................................................................... 17
2. Conformance claims .................................................................................................... 17
2.1. PP-Configuration .................................................................................................. 17
2.1.1. Base-PP: Network Devices ........................................................................ 17
2.1.2. PP-Module: Enterprise Session Controller ................................................. 18
3. Security Problem Definition.......................................................................................... 18
3.1. Threats ................................................................................................................. 18
3.1.1. NDcPP Threats .......................................................................................... 19
3.1.2. MOD_ESC Threats .................................................................................... 20
3.1.3. T.NETWORK_DISCLOSURE..................................................................... 21
3.2. Organizational Security Policies (OSP)................................................................. 21
3.2.1. P.ACCESS_BANNER ................................................................................ 21
3.2.2. P.SECURED_PLATFORM......................................................................... 21
3.3. Assumptions ......................................................................................................... 21
4. Security Objectives ...................................................................................................... 22
4.1. Security Objectives for the TOE............................................................................ 22
4.1.1. O.AUTHORIZED_ADMINISTRATION........................................................ 23
4.1.2. O.MEDIA_RECORDING ............................................................................ 23
4.1.3. O.SECURE_VVOIP.................................................................................... 23
4.1.4. O.SELF_PROTECTION ............................................................................. 23
4.1.5. O.SYSTEM_MONITORING........................................................................ 24
4.2. Security Objectives for the Operational Environment ............................................ 24
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 3 of 76
4.2.1. OE.PHYSICAL ........................................................................................... 24
4.2.2. OE.NO_GENERAL_PURPOSE ................................................................. 24
4.2.3. OE.NO_THRU_TRAFFIC_PROTECTION.................................................. 24
4.2.4. OE.TRUSTED_ADMIN............................................................................... 24
4.2.5. OE.UPDATES............................................................................................ 24
4.2.6. OE.ADMIN_CREDENTIALS_SECURE ...................................................... 25
4.2.7. OE.RESIDUAL_INFORMATION ................................................................ 25
4.2.8. OE.SECURED_PLATFORM ...................................................................... 25
4.3. Security Objectives Rationale ............................................................................... 25
5. Extended Components Definition................................................................................. 27
6. Security Requirements................................................................................................. 28
6.1. Conventions.......................................................................................................... 28
6.2. NDcPP Security Functional Requirements............................................................ 28
6.2.1. Summary.................................................................................................... 28
6.2.2. FAU_GEN.1 Audit data generation............................................................. 30
6.2.3. FAU_GEN.2 User identity association........................................................ 32
6.2.4. FAU_STG_EXT.1 Protected Audit Event Storage ...................................... 32
6.2.5. FCS_CKM.1 Cryptographic Key Generation (Refinement) ......................... 33
6.2.6. FCS_CKM.2 Cryptographic Key Establishment (Refinement)..................... 33
6.2.7. FCS_CKM.4 Cryptographic Key Destruction .............................................. 33
6.2.8. FCS_COP.1 Cryptographic Operation........................................................ 34
6.2.9. Random Bit Generation (Extended – FCS_RBG_EXT) .............................. 35
6.2.10. Authentication Failure Management (FIA_AFL).......................................... 35
6.2.11. Password Management (Extended – FIA_PMG_EXT) ............................... 35
6.2.12. FIA_UIA_EXT.1 User Identification and Authentication .............................. 35
6.2.13. FIA_UAU_EXT.2 Password-based Authentication Mechanism................... 35
6.2.14. FIA_UAU.7 Protected Authentication Feedback ......................................... 36
6.2.15. Management of functions in TSF (FMT_MOF) ........................................... 36
6.2.16. FMT_MTD.1/CoreData Management of TSF Data ..................................... 36
6.2.17. FMT_SMF.1 Specification of Management Functions ................................ 36
6.2.18. FMT_SMR.2 Restrictions on security roles................................................. 37
6.2.19. Protection of TSF Data (Extended – FPT_SKP_EXT) ................................ 37
6.2.20. FPT_APW_EXT.1 Protection of Administrator Passwords.......................... 37
6.2.21. FPT_TST_EXT.1 TSF Testing (Extended) ................................................. 37
6.2.22. FPT_TUD_EXT.1 Trusted Update.............................................................. 37
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 4 of 76
6.2.23. FPT_STM_EXT.1 Reliable Time Stamps ................................................... 38
6.2.24. TSF-initiated Session Locking (Extended – FTA_SSL_EXT)...................... 38
6.2.25. FTA_SSL.3 TSF-initiated Termination (Refinement)................................... 38
6.2.26. FTA_SSL.4 User-initiated Termination (Refinement).................................. 38
6.2.27. FTA_TAB.1 Default TOE Access Banners (Refinement) ............................ 38
6.2.28. FTP_ITC.1 Inter-TSF Trusted Channel (Refinement) ................................. 38
6.2.29. FTP_TRP.1/Admin Trusted Path (Refinement)........................................... 39
6.3. NDcPP Security Assurance Requirements ........................................................... 39
6.4. NDcPP Optional requirements .............................................................................. 39
6.4.1. Auditable events......................................................................................... 39
6.4.2. FCS_TLSC_EXT.2 TLS Client Support for Mutual Authentication .............. 40
6.4.3. FCS_TLSS_EXT.2 TLS Server Support for Mutual Authentication ............. 40
6.5. NDcPP Selection-based requirements.................................................................. 40
6.5.1. Auditable events......................................................................................... 40
6.5.2. FAU_GEN_EXT.1 Security Audit Generation ............................................. 41
6.5.3. FCS_HTTPS_EXT.1 HTTPS Protocol........................................................ 41
6.5.4. FCS_NTP_EXT.1 NTP Protocol................................................................. 41
6.5.5. FCS_SSHS_EXT.1 SSH Server Protocol................................................... 42
6.5.6. FCS_TLSC_EXT.1.1 TLS Client Protocol Without Mutual Authentication... 42
6.5.7. FCS_TLSS_EXT.1 TLS Server Protocol without Mutual Authentication ..... 43
6.5.8. FIA_X509_EXT.1/Rev X.509 Certificate Validation..................................... 44
6.5.9. FIA_X509_EXT.2 X.509 Certificate Authentication..................................... 44
6.5.10. FIA_X509_EXT.3 X.509 Certificate Requests ............................................ 45
6.5.11. FMT_MOF.1/Services Management of Security Functions Behaviour........ 45
6.5.12. FMT_MTD.1/CryptoKeys Management of TSF Data .................................. 45
6.6. MOD_ESC Security Functional Requirements...................................................... 45
6.6.1. Auditable events......................................................................................... 45
6.6.2. Summary.................................................................................................... 46
6.6.3. Security Function Requirements................................................................. 48
6.6.4. FAU_SAR.1/Log Audit Review (System Log) ............................................. 49
6.6.5. FAU_STG.1/CDR Protected Audit Trail Storage (Call Detail Record)......... 49
6.6.6. FAU_VVR_EXT.1 Recording Voice and Video Call Data........................... 49
6.6.7. FDP_IFC.1 Subset Information Flow Control.............................................. 49
6.6.8. FDP_IFF.1 Information Flow Control Functions.......................................... 49
6.6.9. FDP_RIP.1 Subset Residual Information Protection................................... 50
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 5 of 76
6.6.10. FIA_UAU.2/TC User Authentication before Any Action (Telecommunications
Devices) 50
6.6.11. FIA_UAU.2/VVoIP User Authentication before Any Action (VVoIP Endpoints)
50
6.6.12. FMT_CFG_EXT.1 Secure by Default Configuration ................................... 50
6.6.13. FMT_SMF.1/ESC Specification of Management Functions (ESC).............. 50
6.6.14. FPT_FLS.1 Failure with Preservation of a Secure State............................. 50
6.6.15. FTP_ITC.1/ESC Inter-TSF Trusted Channel (ESC Communications)......... 51
6.7. TOE Security Functional Requirements Rationale ................................................ 51
6.8. TOE MOD_ESC Security Assurance Requirements ............................................. 54
7. TOE Summary Specifications ...................................................................................... 54
7.1. NDcPP SFR Enforcing Measures ......................................................................... 54
7.2. MOD_ESC Security Functional Requirement Measures ....................................... 68
7.3. TOE Summary Specification Rationale ................................................................. 73
8. AbBreviations and Acronyms ....................................................................................... 75
Figures
Figure 1 TOE Hardware Platform.......................................................................................... 9
Figure 2 TOE Software Architecture.................................................................................... 12
Figure 3 TOE Deployment Network Diagram ...................................................................... 15
Tables
Table 1 ST and TOE Reference Information ......................................................................... 8
Table 2 Cryptographic algorithms ....................................................................................... 10
Table 3 Secure Communication Ports................................................................................. 16
Table 4 CPP_NDv2.2e Technical Decisions (TD's)............................................................. 17
Table 5 Security Objective Rationale .................................................................................. 25
Table 6 Extended Components........................................................................................... 27
Table 7 NDcPP SFR Summary ........................................................................................... 28
Table 8 Auditable Events .................................................................................................... 31
Table 9 Security Assurance Requirements ......................................................................... 39
Table 10 Option-based Auditable Events ............................................................................ 40
Table 11 Selection-based Auditable Events........................................................................ 40
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 6 of 76
Table 12 TLS Ciphersuites.................................................................................................. 42
Table 13 Extended Auditable Events .................................................................................. 45
Table 14 MOD_ESC SFR Summary ................................................................................... 47
Table 15 System Event Logs .............................................................................................. 48
Table 16 SFT-Objective Rationale ...................................................................................... 51
Table 17 NDcPP SFR Enforcing Measures......................................................................... 54
Table 18 NDcPP SFR Measures......................................................................................... 56
Table 19 Inter-TSF and other client interfaces..................................................................... 63
Table 20 MOD_ESC SFR Measures................................................................................... 68
Table 21 Inter-TSF and other client interfaces..................................................................... 69
Table 22 Abbreviations and Acronyms................................................................................ 75
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 7 of 76
Releases
Issue Description
0.1.0 Initial release
0.2.0 TOE boundary Figs 1&2. Update SFR options & selections. Summary Rationale
0.3.0 Updated according to the evaluator’s feedback
0.4.0 Updated according to the evaluator’s feedback (round2). Changed hw spec
0.5.0 Added - Optional Audit events, TOE Access. Revised TOE Logical architecture
0.6.0 Removed RSA algs from FCS_SSHS_EXT.1.5. Updated Fig.3 and Table 2
0.7.0 Updated according to Acumen’s QA feedback. Added new TD’s
0.7.1 Added missing updates according to previous Acumen QA feedback
0.7.2 Added SSO server in Table 2
0.8.0 Changed conformance from ESC_EP_V1.0 to ESC_MOD_V1.0
0.8.1 Updated according to the evaluator’s feedback (round3). Minor corrections
0.8.2 Updates to Tables 3 & 11. Refined FCS_NTP_EXT.1.2
0.8.3 Removed FMT_MOF.1/AutoUpdate and modified FMT_SMF.1.1 accordingly
0.8.4 Updated TSS and changed FCS_TLSC_EXT.1.2 (RFC 6125)
0.8.5 Added new TD’s and section 2.3. Updated 6.3.6 and TSS descriptions
0.9.1 Updated according to NIAP evaluator feedback 1 and removed FDP_RIP1.1
0.9.2 Provided more detail in TSS descriptions.
0.9.3 Updated TOE name and TSS sections.
0.9.4 Minor updates to address ECR comments.
0.9.5 Added CMVP certificate info. Updated FPT_TST_EXT.1.1 and detail in TSS
0.9.6 Added more detail in TSS according to evaluator’s feedback
0.9.7 Updated TSS under FCS_TLSC_EXT.1 regarding IP addresses in CN
0.9.8 Reverted back to original TSS description for FCS_TLSC_EXT.1
0.9.9 Removed HTTPS from TSS under FIA_AFL.1 based on TD0570 and TD0571
0.9.10 Updated TSS to match FCS_COP.1. Updated TSS for FMT_SMF.1/ESC
0.9.11 Updated TSS based on evaluator feedback
0.9.12 Updated Table 2 and Figure 2. Added RHEL 7.6 in section 1.3.3
1.0.0 Added FDP_RIP.1
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 8 of 76
1. INTRODUCTION
This Security Target (ST) specifies the requirements for the Cellcrypt Server Target of
Evaluation (TOE) for evaluation and accreditation under the Common Criteria (CC).
The format and contents of this ST conforms with Common Criteria (CC), Part 1, Annex A,
and Part 2.
1.1. ST and TOE Reference
Table 1 ST and TOE Reference Information
Attribute Description
ST Title Cellcrypt Server Security Target
ST Version 1.0.0
ST Reference ST-FED-SRV-1
TOE Title Cellcrypt Server
TOE Version 2.5.0
Date June 10, 2022
1.2. Overview
Cellcrypt Server is a secure networking device providing a core set of services for the Cellcrypt
communications network. The Cellcrypt network enables end-to-end encrypted multimedia
communications between users of mobile and desktop computers. Secure multimedia
services include:
• Voice and video (Realtime)
• Text messaging and voice notes (store-and-forward)
• File sharing (store-and-forward)
All network communications are encrypted and interoperability with third-party networks using
standards-based Realtime and store-and-forward protocols (SIP/SRTP/XMPP).
1.3. Description
Cellcrypt Server consists of several services for the management of users, devices and
multimedia networks. These services are integrated in a way that takes advantage of common
proxying and network security interfaces.
1.3.1. Physical Scope of the TOE
The TOE platform consists of Red Hat Enterprise Linux 7.6 64 bit on an Intel Xeon E5-2680
V4 processor with Processor Algorithm Accelerators (PAA). The TOE Hardware is
implemented as a rack-mounted server (see Figure 1).
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 9 of 76
Figure 1 TOE Hardware Platform
The TOE hardware consists of a Hewlett-Packard (HP) rack-mounted server with the following
specifications:
Feature Details
Server Model HP ProLiant DL360p Gen9
Processor 2 x Intel Xeon E5-2680 V4 2.1GHz 8 Core
Chipset family Broadwell
Memory 96GB DDR4 RAM DIMMs
Disk storage 2 x 300GB 3.5-inch SATA hot-plug disks
Smart Array P440ar 12Gbps 2GB Cache RAID Controller
I/O slots Embedded 4x1GbE Network Adapter; Serial Port
Connector (Optional); 3 x PCIe 3.0 Slots; 2 x USB 3.0
Connectors; VGA Video Connector; Dedicated iLO 4
connectors; Flexible LOM bay (Optional)
Ports Front: 2 USB; Rear: 4 USB, video (1600 x 1200), network;
Internal: 1 USB, 1 SD Card
Power Supplies 2 x 800W PSUs
Form Factor 8 Bay SFF 1U Server
Dimensions 19.7 x 19 x 1.75 inches
Weight 40 pounds
1.3.2. Logical Scope of the TOE
The TOE consists of several security functions that make up the logical scope of the TOE:
• Security audit
• Cryptographic support
• Data protection
• Identification and authentication
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 10 of 76
• Security management
• Protection of the TSF
• TOE access
• Trusted path/channels
1.3.2.1. Security Audit
All significant events occurring on the TOE e.g. warnings, errors, and particularly security-
related events are logged by the TOE as audit events. The logs also include Call Detail
Records (CDR’s). All events are uploaded to a remote syslog server protected by a TLS link.
1.3.2.2. Cryptographic Support
All TOE cryptography is performed by the Cellcrypt CCoreV4 FIPS 140-2 validated crypto
module (Certificate A1999). The TOE cryptographic support includes functions supporting key
management, encryption and decryption, random number generation, digital signatures,
secure hashing and keyed secure hashing. Cryptographic protocol support includes TLS,
SSH, HTTPS.
Table 2 Cryptographic algorithms
Algorithms Options Certificates
DRBG (SP 800-90Ar1) CTR_DRBG: (AES-256) CAVP: A1999
AES (FIPS 197) Modes: CTR, CBC, GCM (SP 800-38D)
Key lengths: 128, 256 bits
CAVP: A1999
SHA2 (FIPS 180-4) Hash lengths: 256, 384, 512 CAVP: A1999
HMAC (FIPS 198) Hash lengths: 256, 384, 512 CAVP: A1999
RSA (FIPS 186-2) KeyGen, SigGen, SigVer
Key length: 2048 bits
CAVP: A1999
KAS-ECC-SSC (SP 800-56Ar3) KeyExch
Curves: P-256, P-384, P521
CAVP: A1999
ECDSA (FIPS 186-4) KeyGen, SigGen, SigVer CAVP: A1999
1.3.2.3. Data Protection
The TOE enforces the enterprise session controller SFP on all VVoIP calls and mediates the
data flow between enrolled caller and callee pairs.
1.3.2.4. Identification and Authentication
The TOE enforces role-based authorisation for all administrative access. Administrators must
have a user account on the TOE with an assigned administrative role and the TOE
authenticates administrators by username and password and validates the administrator’s
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 11 of 76
login credentials based on possession of an SSH private key. The TOE also validates X.509v3
certificate access on all TLS ports that make use of client certificates.
1.3.2.5. Security Management
In addition to command line access, the TOE also provides administrators with HTTPS web
portals allowing authorized access to database functionality for administrating user and device
profiles. Access to the web portals is based on username and password.
1.3.2.6. Protection of the TSF
The TOE provides comprehensive protection mechanisms to prevent unauthorised
modification of its software. Built-In Self-Tests (BIST) are used to validate the integrity of all
files stored on the TOE’s persistent storage media and updates to the TOE software are
validated using digital signatures. All file modification events are logged locally and remotely
based on reliable timestamps due the use of an external NTP time source. Warning banners
are used at the start of any interactive session and session inactively timers are used to
terminate inactive sessions.
1.3.2.7. TOE Access
Before any Administrator access to the TOE is established the TOE displays a security banner
with an advisory notice and consent warning message. All inactive Administrator user sessions
are automatically terminated after a preconfigured period. Both Administrators and normal
users can manually terminate sessions at any time requiring re-authentication to the TOE
before establishing a new session.
1.3.2.8. Trusted Path/Channels
All communication channels on the TOE are cryptographically protected and all administrative
interaction is authenticated. ESC SFP is enforced on all user communications based on
authorised user subscriptions.
1.3.3. TOE Logical Architecture
The TOE software architecture, indicating the TOE logical boundary, is shown in Figure 2.
Note that the TOE boundary encapsulates the entire Cellcrypt Server and includes the
operating system Red Hat Enterprise Linux 7.6 64-bit OS (RHEL 7.6).
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 12 of 76
Figure 2 TOE Software Architecture
1.3.4. Network Services
The network services shown in Figure 2 are described in more detail below. The web proxy
(nginx) provides TLS services for the HTTPS virtual hosts using the CCoreV4 module. The
other TLS hosts use CCoreV4 directly for TLS services. Command shell access is protected
with SSH also using the CCoreV4 crypto algorithms. This provides a consistent secure
network interface for the TOE. CCoreV4 is a FIPS 140-2 validated crypto module with its own
validated DRBG receiving seeding from the Intel RDSEED instruction. ECS and the Secure
Gateway provide media conferencing services protected by SRTP. The media relay is simply
a TURN service facilitating SRTP media to traverse NAT routers. The AIDE Intrusion Detection
System (IDS) monitors the file system to detect external hacking.
1.3.4.1. SIP Server
The SIP server provides the main ESC service facilitating all secure voice/video calls by
connecting calls and signalling call progress/status using the SIP protocol in accordance with
RFC 3261. In addition to normal SIP calling services, SDES key management is handled via
the SIP server. The SDES key exchange occurs in the Session Description Protocol (SDP) in
accordance with RFC 4566.
1.3.4.2. Enterprise Management Portal (EMP)
The Enterprise Management Portal provides a secure web application for Enterprise clients to
manage their users. Licenses can be purchased, assigned to users and features can be
enabled or disabled for users within the Enterprise group. The Enterprise Management Portal
Web
Proxy
Database
SIP
Call signalling
ISeed
CCoreV4
SSHD
Admin login
Command
Shell
HTTPS
services
API, EMP, MY,
ECS, Aux, Vault
SRTP media
TOE Logical Boundary
Media
Relay
TLS
links
SSH Admin
XMPP
Gateway
SRTP media
ECS
Ext. Serv.
Auditd, NTPD
AIDE
Audit
File
System
SRTP media
Secure
Gateway
Map
service
RHEL 7.6 OS
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 13 of 76
provides advanced control of the Cellcrypt user’s devices, providing features such as remote
wipe, and information about the user's device, such as operating system and version.
1.3.4.3. MY Server
The MY server is a user-oriented web service, allowing users to manage things like changing
passwords, adding devices to the same account, etc. This service may be limited to
administrator-only usage.
1.3.4.4. API Server
The API server is a web service mainly facilitating secure Suite B messaging. All Cellcrypt
Suite B messaging clients send and retrieve secure messages via the API server. The API
server also provides a general Cellcrypt client API for other housekeeping services.
1.3.4.5. Vault Server
The Vault service provides its own database (MariaDB) for storing message attachments. All
file attachments are encrypted by the clients prior to uploading. The encryption key, together
with the Vault attachment URI is distributed to recipients of the attachment via the Cellcrypt
secure messaging service (see Cryptography section).
1.3.4.6. Enterprise Communications Service
Enterprise Communications Service (ECS) allows administrators to set up scheduled voice
conferences and add users into groups. The group feature allows, not only administrators, but
also users, to create communication groups. Users within groups can communicate with each
other just like a Whatsapp group. Group communication features include messaging,
attachments, voice notes, and normal voice conferencing.
1.3.4.7. Auxiliary service
This service provides general purpose information and configuration options for Cellcrypt
client devices e.g. The latest version of the Cellcrypt client application software can be queried
here.
1.3.4.8. XMPP Server
The XMPP server provides a gateway service between standard XMPP/Jabber messaging
servers and the Cellcrypt Suite B messaging service. The XMPP server interface accepts
XMPP/Jabber messages from its own registered clients, or messages forwarded to its domain
from specific (configured) external XMPP server. External Jabber usernames can be pre-
configured on the server, or automatically added to Cellcrypt contact lists after the first
message sent e.g. in the same way that Cellcrypt messaging automatically adds new contacts.
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 14 of 76
1.3.4.9. MAP Service
The MAP service provides secure mapping information to facilitate secure navigation and
location privacy for field personnel.
1.3.4.10. Secure Gateway
The Secure Gateway (SG) provides a hub for voice mixing in voice conferences. The SG can
bridge calls to a standard PBX as well as standalone SIP phones. Conferences can include a
mixture of Cellcrypt users, PBX SIP/analog phones as well as standalone SIP phones.
1.3.4.11. Secure Shell Host Daemon
This Secure Shell Host Daemon (SSHD) is the standard Linux OpenSSH server which will be
used to provide a command terminal for remote server administration. The SSH protocol is
secured using the common CCoreV4 instance.
1.3.4.12. Audit Daemon
The audit daemon (Auditd) is a standard service on Linux providing a user-space central point
for sending auditable notifications. All security and other important activities are logged using
this service. Auditd is configured to provide remote audit reporting and connects to a remote
audit server. The link to the remote audit server is TLS-secured using the STunnel service
with CCoreV4.
1.3.4.13. Network Time Protocol Daemon
The Network Time Protocol Daemon (NTPD) is a Linux service for synchronizing the server’s
local real-time clock with an online server’s real-time clock using the standard NTP protocol
[Ref 14]. The link to the remote NTP server is TLS-secured using the STunnel service with
CCoreV4.
1.3.4.14. ISeed Entropy gathering Utility
The ISeed utility gathers entropy using the Intel Processor’s RDSEED instruction. The
RDSEED instruction provides access to a high-speed NIST SP800-90B & SP 800-90C(draft)
compliant entropy source. This will ensure that the CCoreV4 DRBG always has sufficient
entropy even under high network usage conditions.
1.3.4.15. Advanced Intrusion Detection Environment
The Advanced Intrusion Detection Environment (AIDE) detects and logs any changes to the
file system. This service is used as a detect-and-alert system to facilitate rapid response to
attempts to hack into the Cellcrypt Server. AIDE is only used to support auditing and integrity
testing. The intrusion detection and prevention capabilities are excluded from the evaluation.
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 15 of 76
1.3.5. Network Deployment Diagram
Figure 3 illustrates a typical TOE deployment network layout showing interoperable access of
client devices. The TOE boundary is clearly identified as including the entire Cellcrypt Server.
Both Cellcrypt and other Third-party devices make use of the standards based Realtime
services (SIP- RFC 3261 and SRTP – RFC 3711). Cellcrypt devices use a proprietary protocol
for messaging and attachments via the API and Vault services. However, messaging
interoperability is achieved using the TOE’s XMPP Gateway service. Third-party XMPP
servers exchange messages with Cellcrypt users via the TOE XMPP Gateway using the
XMPP server-to-server (s2s) protocol (RFC 6120). Third-party SIP and XMPP server-to-server
(s2s) connections can be controlled with TLS authentication and/or VPN.
Although not strictly necessary, a VPN server can be set up in a Demilitarized Zone (DMZ) to
further protect the internal TOE network.
Figure 3 TOE Deployment Network Diagram
1.3.6. List of Secure Communications Ports
The Cellcrypt Server will provide several secure communication ports. These are listed in
Table 3 below. Some TLS interfaces support client authentication with and without mutual
authentication and others support server authentication with and without mutual
authentication. This is because, on the call/message forwarding client interfaces (SIP and
XMPP), we cannot guarantee that external SIP/XMPP servers will support mutual
Federal
Server
CSG Federal
devices
Controlled
Third-party
devices
5269 s2s
XMPP
servers
443 API/AUX/Vault
5061 SIP
5222 XMPP
SIP 5061
XMPP 5222
s2s 5269
SRTP
UDP
SRTP
UDP
SIP 5061
API/Vault 443
MAP 40039
UDP SRTP
SIP 5060
SIP phones
(PBX)
UDP RTP
Network
Admin.
433 EMP/MY/ECS
22 SSH
433 EMP/MY/ECS
22 SSH
123 NTP
11514 Audit
NTP, Audit
and SSO
servers
123 NTP
11514 Audit
Internet
Internet
TOE
TOE Boundary
40039 MAP
3478 UDP TURN
5222/443/5061/5269/40039
443/5269/5061
Push
servers
2196/443
UDP SRTP
Other
servers
5061/443
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 16 of 76
authentication. With the server interfaces we support mutual authentication on the SIP service
but cannot support it on the web portals.
Table 3 Secure Communication Ports
Description Direction Port Protocol
SIP Server (can route to other SIP servers) In/Out 5061 TLS
XMPP Trunk (server-to-server) In/Out 5269 TLS
XMPP Server In 5222 TLS
Remote system administration In 22 SSH
Remote audit server Out 11514 TLS
Remote NTP Time Stamp server Out 123 UDP
Enterprise Management Portal (EMP) In 443 HTTPS/TLS
User Management Portal (MY) In 443 HTTPS/TLS
Enterprise Communication System (ECS) In 443 HTTPS/TLS
Application Services API (Text messaging) In/Out 443 TLS
Vault Server (File attachments) In/Out 443 TLS
Auxiliary Information In/Out 443 TLS
Map server In 40039 TLS
TURN server In 3478 UDP
Conferencing Hub + Media STUN/Turn relay In 16384 –
32767
SRTP
1.3.7. TOE operational components
The TOE’s operational environment consists of several components that fall outside the scope
of the TOE. These non-TOE components consist of the following:
• Peer SIP server – The TOE may contact peer SIP servers from other networks over a
TLS-secured link for Switch-to-Switch communications.
• Remote Audit server – The TOE can send audit logs to a remote syslog server.
• NTP Server – The TOE can contact a remote NTP time server over a TLS-secured
link.
• Push Server. The TOE can send push notifications to mobile client devices by
connecting to a Push Service over a TLS-secured link.
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 17 of 76
1.3.8. TOE Exclusions
AIDE is only used to support auditing and integrity testing and the intrusion detection and
prevention capabilities are excluded from the evaluation.
2. CONFORMANCE CLAIMS
This ST conforms to the requirements of Common Criteria v3.1, Release 5, including CC Part
2 extended and CC Part 3 Conformant.
This ST also conforms to the following PP-Configuration:
2.1. PP-Configuration
The TOE claims exact conformance to the following PP-Configuration:
• PP-Configuration for Network Device and Enterprise Session Controller (ESC), 19
November 2020.
• This PP-Configuration includes the following components:
o Base-PP: collaborative Protection Profile for Network Devices, Version 2.2e
(cPP_ND_V2.2e)
o PP-Module: PP-Module for Enterprise Session Controller (ESC), Version 1.0
(MOD_ESC_V1.0)
Individual PP-Configuration components and all applicable technical decisions are listed
below.
2.1.1. Base-PP: Network Devices
NDcPP
U.S. Government Approved Protection Profile – collaborative Protection Profile for Network
Devices Version 2.2e (cpp_nd_v2.2e)
2.1.1.1. Technical Decisions for the Base-PP
Technical Decisions for cpp_nd_v2.2e listed in Table 4 below.
Table 4 CPP_NDv2.2e Technical Decisions (TD's)
TD No. Applies Description
0592 Yes NIT Technical Decision for Local Storage of Audit Records
0591 No Applies only to virtual TOE’s and hypervisors
0581 Yes NIST SP 800-56A Revision 2 updated to Revision 3 in FCS_CKM.2.1
0580 No N/A. The TOE does not support FFC Schemes
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 18 of 76
TD No. Applies Description
0572 Yes NiT Technical Decision for Restricting FTP_ITC.1 to only IP address
identifiers
0571 Yes NiT Technical Decision for Guidance on how to handle FIA_AFL.1
0570 Yes NiT Technical Decision for Clarification about FIA_AFL.1
0569 Yes NIT Technical Decision for Session ID Usage Conflict in
FCS_DTLSS_EXT.1.7.
0564 Yes NiT Technical Decision for Vulnerability Analysis Search Criteria.
0563 Yes Our audit records already do include the year in the date/time stamp.
0556 Yes Applies to FCS_TLSS_EXT.1.4 Test case 3(a) to be modified.
0555 Yes Applies to FCS_TLSS_EXT.1.4 session resumption testing.
0547 Yes Provide evaluator with additional 3rd-party h/w and s/w information.
0546 No N/A. applies to DTLS. DTLS is not implemented on the TOE.
0538 Yes Updated links to conformance packages and modules.
0537 Yes NIT Technical Decision for Incorrect reference to
FCS_TLSC_EXT.2.3.
0536 Yes NIT Technical Decision for Update Verification Inconsistency.
0528 Yes NIT Technical Decision for Missing EAs for FCS_NTP_EXT.1.4.
0527 Yes Updates to Certificate Revocation Testing (FIA_X509_EXT.1).
2.1.2. PP-Module: Enterprise Session Controller
MOD_ESC
U.S. Government Approved Protection Profile – PP-Module for Enterprise Session Controller
(ESC) Version 1.0 (mod_esc_v1.0)
2.1.2.1. Technical Decisions for the PP-Module
There are no Technical Decisions for MOD_ESC v1.0 as yet.
3. SECURITY PROBLEM DEFINITION
3.1. Threats
The following threats against the TOE are identified below. Note that these include the threats
listed in the NDcPP and MOD_ESC (only the summaries are included).
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 19 of 76
3.1.1. NDcPP Threats
3.1.1.1. T.UNAUTHORIZED_ADMINISTRATOR_ACCESS
Threat agents may attempt to gain Administrator access to the Network Device by nefarious
means such as masquerading as an Administrator to the device, masquerading as the device
to an Administrator, replaying an administrative session (in its entirety, or selected portions),
or performing man-in-the-middle attacks, which would provide access to the administrative
session, or sessions between Network Devices. Successfully gaining Administrator access
allows malicious actions that compromise the security functionality of the device and the
network on which it resides.
3.1.1.2. T.WEAK_CRYPTOGRAPHY
Threat agents may exploit weak cryptographic algorithms or perform a cryptographic exhaust
against the key space. Poorly chosen encryption algorithms, modes, and key sizes will allow
attackers to compromise the algorithms, or brute force exhaust the key space and give them
unauthorized access allowing them to read, manipulate and/or control the traffic with minimal
effort.
3.1.1.3. T.UNTRUSTED_COMMUNICATION_CHANNELS
Threat agents may attempt to target Network Devices that do not use standardized secure
tunnelling protocols to protect the critical network traffic. Attackers may take advantage of
poorly designed protocols or poor key management to successfully perform man-in-the-middle
attacks, replay attacks, etc. Successful attacks will result in loss of confidentiality and integrity
of the critical network traffic, and potentially could lead to a compromise of the Network Device
itself.
3.1.1.4. T.WEAK_AUTHENTICATION_ENDPOINTS
Threat agents may take advantage of secure protocols that use weak methods to authenticate
the endpoints, e.g. a shared password that is guessable or transported as plaintext. The
consequences are the same as a poorly designed protocol, the attacker could masquerade
as the Administrator or another device, and the attacker could insert themselves into the
network stream and perform a man-in-the-middle attack. The result is the critical network traffic
is exposed and there could be a loss of confidentiality and integrity, and potentially the Network
Device itself could be compromised.
3.1.1.5. T.UPDATE_COMPROMISE
Threat agents may attempt to provide a compromised update of the software or firmware
which undermines the security functionality of the device. Non-validated updates or updates
validated using non-secure or weak cryptography leave the update firmware vulnerable to
surreptitious alteration.
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 20 of 76
3.1.1.6. T.UNDETECTED_ACTIVITY
Threat agents may attempt to access, change, and/or modify the security functionality of the
Network Device without Administrator awareness. This could result in the attacker finding an
avenue (e.g., misconfiguration, flaw in the product) to compromise the device and the
Administrator would have no knowledge that the device has been compromised.
3.1.1.7. T.SECURITY_FUNCTIONALITY_COMPROMISE
Threat agents may compromise credentials and device data enabling continued access to the
Network Device and its critical data. The compromise of credentials includes replacing existing
credentials with an attacker’s credentials, modifying existing credentials, or obtaining the
Administrator or device credentials for use by the attacker.
3.1.1.8. T.PASSWORD_CRACKING
Threat agents may be able to take advantage of weak administrative passwords to gain
privileged access to the device. Having privileged access to the device provides the attacker
unfettered access to the network traffic and may allow them to take advantage of any trust
relationships with other Network Devices.
3.1.1.9. T.SECURITY_FUNCTIONALITY_FAILURE
An external, unauthorized entity could make use of failed or compromised security functionality
and might therefore subsequently use or abuse security functions without prior authentication
to access, change or modify device data, critical network traffic or security functionality of the
device.
3.1.2. MOD_ESC Threats
3.1.2.1. T.MALICIOUS_TRAFFIC
A malformed packet is a protocol packet containing modified data not recognizable by the
receiving device (e.g. TOE), or contains modified protocol packets intended to crash or cause
the TOE to act in ways unintended. An attacker may attempt to use a VVoIP endpoint to send
these malformed packets or malicious traffic towards the TOE in an attempt to control or crash
the call control system and connected network devices. To mitigate VVoIP endpoint devices
from being used to successfully launch malicious traffic, the TOE must provide encryption
remedies to prevent modification of protocol packets. The TOE must also provide
authentication mechanisms to prevent unauthorized VVoIP endpoints from improperly
registering to the ESC for the purpose of launching malicious attacks.
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 21 of 76
3.1.3. T.NETWORK_DISCLOSURE
An attacker may attempt to “map” IP addresses of VVoIP endpoint/devices and other
telecommunications equipment for the purpose of determining the organizational structure of
the enterprise, providing reconnaissance for future targeted attacks.
3.1.3.1. T.UNAUTHORIZED_CLIENT
An attacker may attempt to register an unauthorized VVoIP endpoint to the TOE for the
purpose of impersonating a legitimate end user device in order to gain unauthorized
connectivity to other clients or active calls.
3.2. Organizational Security Policies (OSP)
3.2.1. P.ACCESS_BANNER
The TOE shall display an initial banner describing restrictions of use, legal agreements, or any
other appropriate information to which users consent by accessing the TOE.
3.2.2. P.SECURED_PLATFORM
Administrators in the organization ensure that general purpose computers use secure
operating systems and are configured in accordance with applicable security standards
3.3. Assumptions
3.3.1.1. A.PHYSICAL_PROTECTION
The Network Device is assumed to be physically protected in its operational environment and
not subject to physical attacks that compromise the security or interfere with the device’s
physical interconnections and correct operation. This protection is assumed to be sufficient to
protect the device and the data it contains. As a result, the cPP does not include any
requirements on physical tamper protection or other physical attack mitigations. The cPP does
not expect the product to defend against physical access to the device that allows
unauthorized entities to extract data, bypass other controls, or otherwise manipulate the
device. For vNDs, this assumption applies to the physical platform on which the VM runs.
3.3.1.2. A.LIMITED_FUNCTIONALITY
The device is assumed to provide networking functionality as its core function and not provide
functionality/services that could be deemed as general purpose computing. For example, the
device should not provide a computing platform for general purpose applications (unrelated to
networking functionality).
3.3.1.3. A.NO_THRU_TRAFFIC_PROTECTION
A standard/generic Network Device does not provide any assurance regarding the protection
of traffic that traverses it. The intent is for the Network Device to protect data that originates
on or is destined to the device itself, to include administrative data and audit data. Traffic that
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 22 of 76
is traversing the Network Device, destined for another network entity, is not covered by the
ND cPP. It is assumed that this protection will be covered by cPPs and PP-Modules for
particular types of Network Devices (e.g., firewall).
3.3.1.4. A.TRUSTED_ADMINISTRATOR
The Security Administrator(s) for the Network Device are assumed to be trusted and to act in
the best interest of security for the organization. This includes appropriately trained, following
policy, and adhering to guidance documentation. Administrators are trusted to ensure
passwords/credentials have sufficient strength and entropy and to lack malicious intent when
administering the device. The Network Device is not expected to be capable of defending
against a malicious Administrator that actively works to bypass or compromise the security of
the device.
For TOEs supporting X.509v3 certificate-based authentication, the Security Administrator(s)
are expected to fully validate (e.g. offline verification) any CA certificate (root CA certificate or
intermediate CA certificate) loaded into the TOE’s trust store (aka 'root store', ' trusted CA Key
Store', or similar) as a trust anchor prior to use (e.g. offline verification).
3.3.1.5. A.REGULAR_UPDATES
The Network Device firmware and software is assumed to be updated by an Administrator on
a regular basis in response to the release of product updates due to known vulnerabilities.
3.3.1.6. A.ADMIN_CREDENTIALS_SECURE
The Administrator’s credentials (private key) used to access the Network Device are protected
by the platform on which they reside.
3.3.1.7. A.RESIDUAL_INFORMATION
The Administrator must ensure that there is no unauthorized access possible for sensitive
residual information (e.g. cryptographic keys, keying material, PINs, passwords etc.) on
networking equipment when the equipment is discarded or removed from its operational
environment.
4. SECURITY OBJECTIVES
The security objectives are based on the threats and policies listed in the previous section.
Each security objective must match at least one threat or policy. Those listed below include a
reproduction of security objectives listed in the NDcPP and MOD_ESC.
4.1. Security Objectives for the TOE
The following security objectives are identified for the TOE itself. The flowing list of security
objectives come from the MOD_ESC.
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 23 of 76
4.1.1. O.AUTHORIZED_ADMINISTRATION
All network devices are expected to provide services that allow the security functionality of the
device to be managed. The ESC, as a specific type of network device, has a refined set of
management functions to address its specialized behavior.
Addressed by: FAU_STG.1 (refined from Base-PP), FAU_SAR.1/Log, FAU_STG.1/CDR,
FMT_CFG_EXT.1, FMT_SMF.1/ESC, FAU_STG.1/VVR (selection-based)
4.1.2. O.MEDIA_RECORDING
The ESC has the ability to capture and store metadata for the communications it facilitates in
the form of call detail records. It also may optionally capture and store audio/video recordings
of these communications. This data can be used to create a record of potential unauthorized
or malicious activity that is occurring on the network in which the ESC is deployed.
Addressed by: FCS_NTP_EXT.1 (refined from Base-PP), FPT_STM_EXT.1 (refined from
Base-PP), FAU_GEN.1/CDR, FAU_STG.1/CDR, FAU_VVR_EXT.1, FAU_STG.1/VVR
(selection-based), FAU_VVR_EXT.2 (selection-based)
4.1.3. O.SECURE_VVOIP
The ESC has the ability to securely broker VVoIP communications between endpoint devices
as well as external telecommunications equipment. This involves authentication and
encryption of VVoIP communications as well as the enforcement of policies that route valid
traffic to its intended destination while discarding unauthorized traffic flows. The ESC
optionally has the ability to function as an update server for VVoIP software/firmware to ensure
that endpoint devices are securely configured.
Addressed by: FCS_DTLSS_EXT.1 (refined from Base-PP), FCS_DTLSS_EXT.2 (refined
from Base-PP), FCS_NTP_EXT.1 (refined from Base-PP), FCS_TLSC_EXT.1 (refined from
Base-PP), FCS_TLSC_EXT.2 (refined from Base-PP), FCS_TLSS_EXT.1 (refined from Base-
PP), FCS_TLSS_EXT.2 (refined from Base-PP), FIA_X509_EXT.1 (refined from Base-PP),
FIA_X509_EXT.2 (refined from Base-PP), FIA_X509_EXT.3 (refined from Base-PP),
FPT_STM_EXT.1 (refined from Base-PP), FDP_IFC.1, FDP_IFF.1, FIA_UAU.2/TC,
FIA_UAU.2/VVoIP, FTP_ITC.1/ESC, FPT_TUD_EXT.1/VVoIP (implementation-dependent)
4.1.4. O.SELF_PROTECTION
The ESC has the ability to capture diagnostic data about its own functionality in real-time so
that anomalous behavior or failures can be diagnosed. The ESC also has the ability to respond
securely if a failure state is detected so that a crash of the TOE cannot be used to facilitate
malicious activity. The ESC also enforces purging of residual data so that security-relevant
information cannot be obtained from a decommissioned or refurbished device.
Addressed by: FAU_GEN.1/Log , FDP_RIP.1 and FPT_FLS.1
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 24 of 76
4.1.5. O.SYSTEM_MONITORING
In order to ensure that potentially malicious activity is detected, the NDcPP requires security-
relevant events to be audited. The ESC also provides security functions to support system
monitoring for the functionality that it adds to the NDcPP. This includes the generation of audit
records and system log data, the secure storage and ability to review stored data with
authorization, and optionally the ability to suppress the generation of certain audit records to
reduce log volume as a means to decrease the likelihood that a critical event is overlooked.
Addressed by: FAU_GEN.1 (refined from Base-PP), FAU_STG.1 (refined from Base-PP),
FCS_NTP_EXT.1 (refined from Base-PP), FPT_STM_EXT.1 (refined from Base-PP),
FAU_GEN.1/Log, FAU_SAR.1/Log, FAU_SEL.1 (selection-based)
4.2. Security Objectives for the Operational Environment
4.2.1. OE.PHYSICAL
Physical security, commensurate with the value of the TOE and the data it contains, is
provided by the environment.
4.2.2. OE.NO_GENERAL_PURPOSE
There are no general-purpose computing capabilities (e.g., compilers or user applications)
available on the TOE, other than those services necessary for the operation, administration
and support of the TOE. Note: For vNDs the TOE includes only the contents of the its own
VM, and does not include other VMs or the VS.
4.2.3. OE.NO_THRU_TRAFFIC_PROTECTION
The TOE does not provide any protection of traffic that traverses it. It is assumed that
protection of this traffic will be covered by other security and assurance measures in the
operational environment.
4.2.4. OE.TRUSTED_ADMIN
Security Administrators are trusted to follow and apply all guidance documentation in a trusted
manner. For vNDs, this includes the VS Administrator responsible for configuring the VMs that
implement ND functionality.
For TOEs supporting X.509v3 certificate-based authentication, the Security Administrator(s)
are assumed to monitor the revocation status of all certificates in the TOE's trust store and to
remove any certificate from the TOE’s trust store in case such certificate can no longer be
trusted.
4.2.5. OE.UPDATES
The TOE firmware and software is updated by an Administrator on a regular basis in response
to the release of product updates due to known vulnerabilities.
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 25 of 76
4.2.6. OE.ADMIN_CREDENTIALS_SECURE
The Administrator’s credentials (private key) used to access the TOE must be protected on
any other platform on which they reside.
4.2.7. OE.RESIDUAL_INFORMATION
The Security Administrator ensures that there is no unauthorized access possible for sensitive
residual information (e.g. cryptographic keys, keying material, PINs, passwords etc.) on
networking equipment when the equipment is discarded or removed from its operational
environment. For vNDs, this applies when the physical platform on which the VM runs is
removed from its operational environment.
4.2.8. OE.SECURED_PLATFORM
The operating system of the network device does not provide an interface or other capability
that can be used to adversely affect the TOE or its own functionality.
4.3. Security Objectives Rationale
This section describes how the assumptions, threats, and organizational security policies map
to the security objectives. Note that this section only provides mappings for the security
objectives defined in the MOD_ESC.
Table 5 Security Objective Rationale
Objective Threat or OSP Rationale
O.AUTHORIZED_ADMINIS
TRATION
T.UNAUTHORIZED_ADMINISTR
ATOR_ACCESS (from Base-PP)
The TOE further mitigates the threat of
unauthorized administrator access
defined in the Base-PP by defining
additional TSF management functions
that are specific to ESC functionality
with the expectation that they are
authorized in the same manner as
Base-PP management functions.
O.MEDIA_RECORDING T.MALICIOUS_TRAFFIC The TOE mitigates the threat of
malicious traffic by recording VVoIP
communications so that potential
sources of malicious traffic can be
identified.
O.SECURE_VVOIP P.SECURED_PLATFORM The organizational security policy that
expects secure configuration of
environmental systems helps satisfy
the secure VVoIP objective by reducing
the likelihood that a malicious user has
compromised a system with a VVoIP
endpoint on it.
T.MALICIOUS_TRAFFIC The TOE mitigates the threat of
malicious traffic by ensuring that all
connected VVoIP and
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 26 of 76
Objective Threat or OSP Rationale
telecommunications devices are
authenticated and that information will
only flow through the TOE if it is
validated by the TSF.
T.NETWORK_DISCLOSURE The TOE mitigates the threat of network
disclosure by ensuring that all
connected VVoIP communications are
encrypted.
T.UNAUTHORIZED_CLIENT The TOE mitigates the threat of
unauthorized client connectivity by
requiring endpoint devices to be
authenticated and by implementing
encryption to prevent spoofing.
O.SELF_PROTECTION T.MALICIOUS_TRAFFIC The TOE mitigates the threat of
malicious traffic by enforcing self-
protection mechanisms to ensure that
the TOE receiving malicious traffic will
not cause it to fail to enforce its security
functionality.
T.UNDETECTED_ACTIVITY
(from Base-PP)
The TOE further mitigates the threat of
undetected activity defined in the Base-
PP by enforcing the monitoring of
behavior that is specific to ESC
functionality.
O.SYSTEM_MONITORING T.UNAUTHORIZED_CLIENT The TOE mitigates the threat of
unauthorized client access by
monitoring system activity so that an
audit trail of all client activity exists for
future analysis if malicious activity is
discovered.
T.UNDETECTED_ACTIVITY
(from Base-PP)
The TOE further mitigates the threat of
undetected activity defined in the Base-
PP by enforcing the monitoring of
behavior that is specific to ESC
functionality.
OE.SECURED_PLATFORM P.SECURED_PLATFORM In order to ensure that the ESC is not
subject to compromise, it is important
for the OS that it is installed on to be
secure in terms of closing unnecessary
interfaces and providing appropriate
security functionality. However, it is
necessary for this PP-Module to make
this an organizational policy in the
scenario where the TOE uses a
commercial third-party OS because the
ESC vendor is not responsible for
providing the OS and therefore has no
control over its inherent functionality or
administrative configuration.
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 27 of 76
5. EXTENDED COMPONENTS DEFINITION
The extended components i.e. those not defined in CC Part 2 or CC Part 3 are listed in Table
6 below. These are from the NDcPP and MOD_ESC.
Table 6 Extended Components
PP SFR Description
MOD_ESC FAU_STG_EXT.1 Recording Voice and Video Call Data
NDcPP FAU_STG_EXT.1 Protected Audit Event Storage
NDcPP FCS_HTTPS_EXT.1 HTTPS Protocol
NDcPP FCS_RBG_EXT.1 Random Bit Generation
NDcPP FCS_SSHS_EXT.1 SSH Server Protocol
NDcPP FCS_TLSC_EXT.2 TLS Client Protocol with authentication
NDcPP FCS_TLSS_EXT.1 TLS Server Protocol
NDcPP FCS_TLSS_EXT.2 TLS Server Protocol with mutual authentication
NDcPP FIA_PMG_EXT.1 Password Management
NDcPP FIA_UAU_EXT.2 Password-based Authentication Mechanism
NDcPP FIA_UIA_EXT.1 User Identification and Authentication
NDcPP FIA_X509_EXT.1/Rev X.509 Certificate Validation
MOD_ESC FIA_X509_EXT.2 X.509 Certificate Authentication
NDcPP FIA_X509_EXT.2 X.509 Certificate Authentication
NDcPP FIA_X509_EXT.3 X.509 Certificate Requests
MOD_ESC FMT_CFG_EXT.1 Secure by Default Configuration
NDcPP FPT_APW_EXT.1 Protection of Administrator Passwords
NDcPP FPT_SKP_EXT.1 Protection of TSF Data (for reading of all pre-shared,
symmetric and private keys)
NDcPP FPT_STM_EXT.1 Reliable Time Stamps
NDcPP FPT_TST_EXT.1 TSF testing
NDcPP FPT_TUD_EXT.1 Trusted update
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 28 of 76
PP SFR Description
NDcPP FTA_SSL_EXT.1 TSF-initiated Session Locking
6. SECURITY REQUIREMENTS
This section identifies the Security Functional Requirements for the TOE and/or Platform.
6.1. Conventions
The CC defines operations on Security Functional Requirements: assignments, selections,
assignments within selections and refinements. This document uses the following font
conventions to identify the operations performed in the ST:
• Unaltered SFRs are stated in the form used in [CC2] or their extended component
definition (ECD);
• Refinement: indicated with bold text and strikethroughs;
• Assignment: Indicated with italicized text;
• Selection: Indicated with underlined text;
• Assignment within a Selection: Indicated with underlined bold italics text.
Note: The font conventions for Assignments and Assignments within a Selection overlap with
existing NDcPP, MOD_ESC or formatting.
The ST does not perform any iteration operations.
6.2. NDcPP Security Functional Requirements
6.2.1. Summary
The NDcPP Security Functional Requirements (SFR’s) are specified in this section. The
NDcPP SFR’s are summarized in Table 7 below.
Table 7 NDcPP SFR Summary
Class Name Component Identification Component Name
FAU: Security audit FAU_GEN.1 Audit data generation
FAU_GEN.2 User identity association
FAU_STG_EXT.1 External Audit Trail Storage
FCS: Cryptographic
support
FCS_CKM.1 Cryptographic Key Generation
FCS_CKM.2 Cryptographic Key Establishment
FCS_CKM.4 Cryptographic Key Destruction
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 29 of 76
Class Name Component Identification Component Name
FCS_COP.1/DataEncryption Cryptographic Operation (AES Data
Encryption/Decryption)
FCS_COP.1/SigGen Cryptographic Operation (Signature
Generation and Verification)
FCS_COP.1/Hash Cryptographic Operation (Hash
Algorithm)
FCS_COP.1/KeyedHash Cryptographic Operation (Keyed-
hash Algorithm)
FCS_RBG_EXT.1 Random Bit Generation
FCS_HTTPS_EXT.1 HTTPS Protocol
FCS_SSHS_EXT.1 SSH Server Protocol
FCS_TLSC_EXT.1 TLS Client Protocol without mutual
authentication
FCS_TLSC_EXT.2 TLS Client Protocol with mutual
authentication
FCS_TLSS_EXT.1 TLS Server Protocol without mutual
authentication
FCS_TLSS_EXT.2 TLS Server Protocol with mutual
authentication
FCS_NTP_EXT.1 NTP Protocol
FIA: Identification and
authentication
FIA_AFL.1 Authentication Failure Management
FIA_PMG_EXT.1 Password Management
FIA_UIA_EXT.1 User Identification and Authentication
FIA_UAU_EXT.2 Password-based Authentication
Mechanism
FIA_UAU.7 Protected Authentication Feedback
FIA_X509_EXT.1/Rev X.509 Certificate Validation
FIA_X509_EXT.2 X.509 Certificate Authentication
FIA_X509_EXT.3 X.509 Certificate Requests
FMT: Security
management
FMT_MOF.1/ManualUpdate Management of SF behaviour
FMT_MOF.1/Services Management of SF behaviour
FMT_MTD.1/CoreData Management of TSF Data
FMT_MTD.1/CryptoKeys Management of TSF Data
FMT_SMF.1 Specification of Management
Functions
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 30 of 76
Class Name Component Identification Component Name
FMT_SMR.2 Restrictions on Security Roles
FPT: Protection of the
TSF
FPT_SKP_EXT.1 Protection of TSF Data (for reading
of all pre-shared, symmetric and
private keys)
FPT_APW_EXT.1 Protection of Administrator
Passwords
FPT_TST_EXT.1 TSF testing
FPT_TUD_EXT.1 Trusted update
FPT_STM_EXT.1 Reliable Time Stamps
FTA: TOE access FTA_SSL_EXT.1 TSF-initiated Session Locking
FTA_SSL.3 TSF-initiated Termination
FTA_SSL.4 User-initiated Termination
FTA_TAB.1 Default TOE Access Banners
FTP: Trusted
path/channels
FTP_ITC.1 Inter-TSF trusted channel
FTP_TRP.1/Admin Trusted Path
6.2.2. FAU_GEN.1 Audit data generation
FAU_GEN.1.1 The TSF shall be able to generate an audit record of the following auditable
events:
a) Start-up and shut-down of the audit functions;
b) All auditable events for the not specified level of audit; and
c) All administrative actions comprising:
• Administrative login and logout (name of user account shall be logged if individual user
accounts are required for Administrators).
• Changes to TSF data related to configuration changes (in addition to the information
that a change occurred it shall be logged what has been changed).
• Generating/import of, changing, or deleting of cryptographic keys (in addition to the
action itself a unique key name or key reference shall be logged).
• Resetting passwords (name of related user account shall be logged).
• No other actions
d) Specifically defined auditable events listed in Table 8.
FAU_GEN.1.2 The TSF shall record within each audit record at least the following information:
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 31 of 76
a) Date and time of the event, type of event, subject identity, and the outcome (success
or failure) of the event; and
b) For each audit event type, based on the auditable event definitions of the functional
components included in the cPP/ST, information specified in column three of Table 8.
Table 8 Auditable Events
Requirement Auditable Events Additional Record Contents
FAU_GEN.1 None. None.
FAU_GEN.2 None. None.
FAU_STG_EXT.1 None. None.
FCS_CKM.1 None. None.
FCS_CKM.2 None. None.
FCS_CKM.4 None. None.
FCS_COP.1/DataEncryption None. None.
FCS_COP.1/SigGen None. None.
FCS_COP.1/Hash None. None.
FCS_COP.1/KeyedHash None. None.
FCS_RBG_EXT.1 None. None.
FIA_AFL.1 Unsuccessful login attempts
limit is met or exceeded.
Origin of the attempt (e.g., IP
address).
FIA_PMG_EXT.1 None. None.
FIA_UIA_EXT.1 All use of identification and
authentication mechanism.
Origin of the attempt (e.g., IP
address).
FIA_UAU_EXT.2 All use of identification and
authentication mechanism.
Origin of the attempt (e.g., IP
address).
FIA_UAU.7 None. None.
FMT_MOF.1/ManualUpdate Any attempt to initiate a
manual update.
None.
FMT_MTD.1/CoreData None. None.
FMT_SMF.1 All management activities of
TSF data.
None.
FMT_SMR.2 None. None.
FPT_SKP_EXT.1 None. None.
FPT_APW_EXT.1 None. None.
FPT_TST_EXT.1 None. None.
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 32 of 76
Requirement Auditable Events Additional Record Contents
FPT_TUD_EXT.1 Initiation of update; result of
the update attempt (success
or failure).
None.
FPT_STM_EXT.1 Discontinuous changes to
time - either Administrator
actuated or changed via an
automated process. (Note
that no continuous changes
to time need to be logged.
See also application note on
FPT_STM_EXT.1).
For discontinuous changes to
time: The old and new values
for the time. Origin of the
attempt to change time for
success and failure (e.g., IP
address).
FTA_SSL_EXT.1 (if
“terminate the session” is
selected)
The termination of a local
session by the session
locking mechanism.
None.
FTA_SSL.3 The termination of a remote
session by the session
locking mechanism.
None.
FTA_SSL.4 The termination of an
interactive session.
None.
FTA_TAB.1 None. None.
FTP_ITC.1 • Initiation of the trusted
channel.
• Termination of the trusted
channel.
• Failure of the trusted
channel functions.
Identification of the initiator
and target of failed trusted
channels establishment
attempt.
FTP_TRP.1/Admin • Initiation of the trusted
channel.
• Termination of the trusted
channel.
• Failure of the trusted
channel functions.
None.
6.2.3. FAU_GEN.2 User identity association
FAU_GEN.2.1 For audit events resulting from actions of identified users, the TSF shall be
able to associate each auditable event with the identity of the user that caused the event.
6.2.4. FAU_STG_EXT.1 Protected Audit Event Storage
FAU_STG_EXT.1.1 The TSF shall be able to transmit the generated audit data to an external
IT entity using a trusted channel according to FTP_ITC.1.
FAU_STG_EXT.1.2 The TSF shall be able to store generated audit data on the TOE itself. In
addition
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 33 of 76
• the TOE shall consist of a single standalone component that stores audit data locally.
FAU_STG_EXT.1.3 The TSF shall overwrite previous audit records according to the following
rule: overwrite starting from oldest records when the local storage space for audit data is
full.
6.2.5. FCS_CKM.1 Cryptographic Key Generation (Refinement)
FCS_CKM.1.1 The TSF shall generate asymmetric cryptographic keys in accordance with a
specified cryptographic key generation algorithm: [
• RSA schemes using cryptographic key sizes of 2048-bit or greater that meet the
following: FIPS PUB 186-4, “Digital Signature Standard (DSS)”, Appendix B.3;
• ECC schemes using ‘NIST curves’ P-256, P-384, P-521 that meet the following: FIPS
PUB 186-4, “Digital Signature Standard (DSS)”, Appendix B.4;
• FFC Schemes using ‘safe-prime’ groups that meet the following: “NIST Special
Publication 800-56A Revision 3, Recommendation for Pair-Wise Key Establishment
Schemes Using Discrete Logarithm Cryptography” and RFC 3526.
] and specified cryptographic key sizes [assignment: cryptographic key sizes] that meet
the following: [assignment: list of standards].
6.2.6. FCS_CKM.2 Cryptographic Key Establishment (Refinement)
FCS_CKM.2.1 The TSF shall perform cryptographic key establishment in accordance with
a specified cryptographic key establishment method: [
• RSA-based key establishment schemes that meet the following: RSAES-PKCS1-v1_5
as specified in Section 7.2 of RFC 3447, “Public-Key Cryptography Standards (PKCS)
#1: RSA Cryptography Specifications Version 2.1”;
• Elliptic curve-based key establishment schemes that meet the following: NIST Special
Publication 800-56A Revision 3, “Recommendation for Pair-Wise Key Establishment
Schemes Using Discrete Logarithm Cryptography”;
• FFC Schemes using ‘safe-prime’ groups that meet the following: “NIST Special
Publication 800-56A Revision 3, Recommendation for Pair-Wise Key Establishment
Schemes Using Discrete Logarithm Cryptography” and RFC 3526.
] that meets the following: [assignment: list of standards].
6.2.7. FCS_CKM.4 Cryptographic Key Destruction
FCS_CKM.4.1 The TSF shall destroy cryptographic keys in accordance with a specified
cryptographic key destruction method [
• For plaintext keys in volatile storage, the destruction shall be executed by a single
overwrite consisting of zeroes;
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 34 of 76
• For plaintext keys in non-volatile storage, the destruction shall be executed by the
invocation of an interface provided by a part of the TSF that
o logically addresses the storage location of the key and performs a single-pass
overwrite consisting of a new value of the key;
]
that meets the following: No Standard.
6.2.8. FCS_COP.1 Cryptographic Operation
FCS_COP.1.1/DataEncryption The TSF shall perform encryption/decryption in accordance
with a specified cryptographic algorithm AES used in CBC, CTR, GCM mode and
cryptographic key size 128 bits, 256 bits that meet the following: AES as specified in ISO
18033-3, CBC as specified in ISO 10116, CTR as specified in ISO
10116, GCM as specified in ISO 19772.
FCS_COP.1.1/SigGen The TSF shall perform cryptographic signature services (generation
and verification) in accordance with a specified cryptographic algorithm: [
• RSA Digital Signature Algorithm and cryptographic key sizes (modulus) 2048 bits or
greater,
• Elliptic Curve Digital Signature Algorithm and cryptographic key sizes 256 bits or
greater
]
that meet the following: [
• For RSA schemes: FIPS PUB 186-4, “Digital Signature Standard (DSS)”, Section 5.5,
using PKCS #1 v2.1 Signature Schemes RSASSA-PSS and/or RSASSA-PKCS1v1_5;
ISO/IEC 9796-2, Digital signature scheme 2 or Digital Signature scheme 3,
• For ECDSA schemes: FIPS PUB 186-4, “Digital Signature Standard (DSS)”, Section
6 and Appendix D, Implementing “NIST curves” [selection: P-256, P-384, P-521];
ISO/IEC 14888-3, Section 6.4
]
FCS_COP.1.1/Hash The TSF shall perform cryptographic hashing services in accordance
with a specified cryptographic algorithm SHA-256, SHA-384, SHA-512 and cryptographic key
sizes [assignment: cryptographic key sizes] and message digest sizes 256, 384, 512 bits
that meet the following: ISO/IEC 10118-3:2004.
FCS_COP.1.1/KeyedHash The TSF shall perform keyed-hash message authentication in
accordance with a specified cryptographic algorithm HMAC-SHA-256, HMAC-SHA-384,
HMAC-SHA-512 and cryptographic key size [256, 384 and 512 bits used in HMAC] and
message digest sizes 256, 384, 512 bits that meet the following: ISO/IEC 9797-2:2011,
Section 7 “MAC Algorithm 2”.
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 35 of 76
6.2.9. Random Bit Generation (Extended – FCS_RBG_EXT)
FCS_RBG_EXT.1.1 The TSF shall perform all deterministic random bit generation services in
accordance with ISO/IEC 18031:2011 using CTR_DRBG (AES).
FCS_RBG_EXT.1.2 The deterministic RBG shall be seeded by at least one entropy source
that accumulates entropy from platform-based noise source with a minimum of 256 bits of
entropy at least equal to the greatest security strength, according to ISO/IEC 18031:2011
Table C.1 “Security Strength Table for Hash Functions”, of the keys and hashes that it will
generate.
6.2.10. Authentication Failure Management (FIA_AFL)
FIA_AFL.1.1 The TSF shall detect when an Administrator configurable positive integer within
6 unsuccessful authentication attempts occur related to Administrators attempting to
authenticate remotely using a password.
FIA_AFL.1.2 When the defined number of unsuccessful authentication attempts has been
met, the TSF shall prevent the offending Administrator from successfully establishing a remote
session using any authentication method that involves a password until an Administrator
defined time period has elapsed.
6.2.11. Password Management (Extended – FIA_PMG_EXT)
FIA_PMG_EXT.1.1 The TSF shall provide the following password management capabilities
for administrative passwords:
a) Passwords shall be able to be composed of any combination of upper and lower case
letters, numbers, and the following special characters: [“!”, “@”, “#”, “$”, “%”, “^”, “&”, “*”, “(“,
“)”, [“[“, “]”, “{“, “}”, “:”, “;”]];
b) Minimum password length shall be configurable to between 9 and 20 characters.
6.2.12. FIA_UIA_EXT.1 User Identification and Authentication
FIA_UIA_EXT.1.1 The TSF shall allow the following actions prior to requiring the non-TOE
entity to initiate the identification and authentication process:
• Display the warning banner in accordance with FTA_TAB.1;
• no other actions.
FIA_UIA_EXT.1.2 The TSF shall require each administrative user to be successfully identified
and authenticated before allowing any other TSF-mediated actions on behalf of that
administrative user.
6.2.13. FIA_UAU_EXT.2 Password-based Authentication Mechanism
FIA_UAU_EXT.2.1 The TSF shall provide a local password-based, SSH public key-based
authentication mechanism to perform local administrative user authentication.
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 36 of 76
6.2.14. FIA_UAU.7 Protected Authentication Feedback
FIA_UAU.7.1 The TSF shall provide only obscured feedback to the administrative user while
the authentication is in progress at the local console.
6.2.15. Management of functions in TSF (FMT_MOF)
FMT_MOF.1.1/ManualUpdate The TSF shall restrict the ability to enable the functions to
perform manual updates to Security Administrators.
6.2.16. FMT_MTD.1/CoreData Management of TSF Data
FMT_MTD.1.1/CoreData The TSF shall restrict the ability to manage the TSF data to Security
Administrators.
6.2.17. FMT_SMF.1 Specification of Management Functions
FMT_SMF.1.1 The TSF shall be capable of performing the following management functions:
• Ability to administer the TOE locally and remotely;
• Ability to configure the access banner;
• Ability to configure the session inactivity time before session termination or locking;
• Ability to update the TOE, and to verify the updates using hash comparison capability
prior to installing those updates;
• Ability to enable/disable voice and video recordings for any registered VVoIP
endpoint;
• Ability to display the real-time connection status of all VVoIP endpoints
(hardware and software) and telecommunications devices;
• Ability to clear all TSF data stored on disk;
• Ability to configure the authentication failure parameters for FIA_AFL.1;
• [
o Ability to start and stop services;
o Ability to configure audit behaviour (e.g. changes to storage locations for
audit; changes to behaviour when local audit storage space is full);
o Ability to modify the behaviour of the transmission of audit data to an external
IT entity, the handling of audit data, the audit functionality when Local
Audit Storage Space is full;
o Ability to configure the list of TOE-provided services available before an entity
is identified and authenticated, as specified in FIA_UIA_EXT.1;
o Ability to manage the cryptographic keys;
o Ability to configure the cryptographic functionality;
o Ability to configure thresholds for SSH rekeying;
o Ability to configure the interaction between TOE components;
o Ability to re-enable an Administrator account;
o Ability to set the time which is used for time-stamps;
o Ability to configure NTP;
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 37 of 76
o Ability to configure the reference identifier for the peer;
o Ability to manage the TOE's trust store and designate X509.v3 certificates as
trust anchors;
o Ability to import X.509v3 certificates to the TOE's trust store;
o Ability to configure the password policy;
o Ability to specify the set of audited events;
o No other capabilities
].
6.2.18. FMT_SMR.2 Restrictions on security roles
FMT_SMR.2.1 The TSF shall maintain the roles:
• Security Administrator.
FMT_SMR.2.2 The TSF shall be able to associate users with roles.
FMT_SMR.2.3 The TSF shall ensure that the conditions
• The Security Administrator role shall be able to administer the TOE locally;
• The Security Administrator role shall be able to administer the TOE remotely
•
are satisfied.
6.2.19. Protection of TSF Data (Extended – FPT_SKP_EXT)
FPT_SKP_EXT.1.1 The TSF shall prevent reading of all pre-shared keys, symmetric keys,
and private keys.
6.2.20. FPT_APW_EXT.1 Protection of Administrator Passwords
FPT_APW_EXT.1.1 The TSF shall store administrative passwords in non-plaintext form.
FPT_APW_EXT.1.2 The TSF shall prevent the reading of plaintext administrative passwords.
6.2.21. FPT_TST_EXT.1 TSF Testing (Extended)
FPT_TST_EXT.1.1 The TSF shall run a suite of the following self-tests during initial start-up
(on power on), at the request of the authorised user to demonstrate the correct operation of
the TSF. [The following tests can be run:
• System Power On Self-Test (POST)
• Cryptography self-test
]
6.2.22. FPT_TUD_EXT.1 Trusted Update
FPT_TUD_EXT.1.1 The TSF shall provide Security Administrators the ability to query the
currently executing version of the TOE firmware/software and the most recently installed
version of the TOE firmware/software.
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 38 of 76
FPT_TUD_EXT.1.2 The TSF shall provide Security Administrators the ability to manually
initiate updates to TOE firmware/software and no other update mechanism.
FPT_TUD_EXT.1.3 The TSF shall provide means to authenticate firmware/software updates
to the TOE using a published hash prior to installing those updates.
6.2.23. FPT_STM_EXT.1 Reliable Time Stamps
FPT_STM_EXT.1.1 The TSF shall be able to provide reliable time stamps for its own use.
FPT_STM_EXT.1.2 The TSF shall synchronise time with an NTP server.
6.2.24. TSF-initiated Session Locking (Extended – FTA_SSL_EXT)
FTA_SSL_EXT.1.1 The TSF shall, for local interactive sessions, terminate the session
after a Security Administrator-specified time period of inactivity.
6.2.25. FTA_SSL.3 TSF-initiated Termination (Refinement)
FTA_SSL.3.1: The TSF shall terminate a remote interactive session after a Security
Administrator-configurable time interval of session inactivity.
6.2.26. FTA_SSL.4 User-initiated Termination (Refinement)
FTA_SSL.4.1: The TSF shall allow Administrator-initiated termination of the
Administrator’s own interactive session.
6.2.27. FTA_TAB.1 Default TOE Access Banners (Refinement)
FTA_TAB.1.1: Before establishing an administrative user session the TSF shall display a
Security Administrator-specified advisory notice and consent warning message regarding
use of the TOE.
6.2.28. FTP_ITC.1 Inter-TSF Trusted Channel (Refinement)
FTP_ITC.1.1 The TSF shall be capable of using HTTPS, TLS to provide a trusted
communication channel between itself and authorized IT entities supporting the following
capabilities: audit server, XMPP server, Cellcrypt Clients for non-VVoIP communication
that is logically distinct from other communication channels and provides assured identification
of its end points and protection of the channel data from disclosure and detection of
modification of the channel data.
FTP_ITC.1.2 The TSF shall permit the TSF or the authorized IT entities to initiate
communication via the trusted channel.
FTP_ITC.1.3 The TSF shall initiate communication via the trusted channel for [
• remote auditing
• relaying XMPP messages from the XMPP gateway service to other XMPP servers
].
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 39 of 76
6.2.29. FTP_TRP.1/Admin Trusted Path (Refinement)
FTP_TRP.1.1/Admin The TSF shall be capable of using SSH, HTTPS to provide a
communication path between itself and authorized remote Administrators that is logically
distinct from other communication paths and provides assured identification of its end points
and protection of the communicated data from disclosure and provides detection of
modification of the channel data.
FTP_TRP.1.2/Admin The TSF shall permit remote Administrators to initiate communication
via the trusted path.
FTP_TRP.1.3/Admin The TSF shall require the use of the trusted path for initial Administrator
authentication and all remote administration actions.
6.3. NDcPP Security Assurance Requirements
The NDcPP Security Assurance Requirements, as reproduced from the NDcPP protection
profile, are summarized in Table 9 below.
Table 9 Security Assurance Requirements
Assurance Class Assurance Components
Security Target (ASE) Conformance claims (ASE_CCL.1)
Extended components definition (ASE_ECD.1)
ST introduction (ASE_INT.1)
Security objectives for the operational environment
(ASE_OBJ.1)
Stated security requirements (ASE_REQ.1)
Security Problem Definition (ASE_SPD.1)
TOE summary specification (ASE_TSS.1)
Development (ADV) Basic functional specification (ADV_FSP.1)
Guidance Documents (AGD) Operational user guidance (AGD_OPE.1)
Preparative procedures (AGD_PRE.1)
Life Cycle Support (ALC) Labelling of the TOE (ALC_CMC.1)
TOE CM coverage (ALC_CMS.1)
Tests (ATE) Independent testing – conformance (ATE_IND.1)
Vulnerability Assessment (AVA) Vulnerability survey (AVA_VAN.1)
6.4. NDcPP Optional requirements
6.4.1. Auditable events
Table 10 lists the option-based auditable events that serve to extend FAU_GEN.1.
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 40 of 76
Table 10 Option-based Auditable Events
SFR Auditable Event Additional Audit Record
Contents
FCS_TLSC_EXT.2 None None
FCS_TLSS_EXT.2 Failure to authenticate the
client
Reason for failure
6.4.2. FCS_TLSC_EXT.2 TLS Client Support for Mutual Authentication
FCS_TLSC_EXT.2.1 The TSF shall support TLS communication with mutual authentication
using X.509v3 certificates.
6.4.3. FCS_TLSS_EXT.2 TLS Server Support for Mutual Authentication
FCS_TLSS_EXT.2.1 The TSF shall support TLS communication with mutual authentication
of TLS clients using X.509v3 certificates.
FCS_TLSS_EXT.2.2 When establishing a trusted channel, by default the TSF shall not
establish a trusted channel if the client certificate is invalid. The TSF shall also Not implement
any administrator override mechanism.
FCS_TLSS_EXT.2.3 The TSF shall not establish a trusted channel if the identifier contained
in a certificate does not match an expected identifier for the client. If the identifier is a Fully
Qualified Domain Name (FQDN), then the TSF shall match the identifiers according to RFC
6125, otherwise the TSF shall parse the identifier from the certificate and match the identifier
against the expected identifier of the client as described in the TSS.
6.5. NDcPP Selection-based requirements
6.5.1. Auditable events
Table 11 lists the selection-based auditable events that serve to extend FAU_GEN.1.
Table 11 Selection-based Auditable Events
SFR Auditable Event Additional Audit Record
Contents
FCS_HTTPS_EXT.1 Failure to establish a HTTPS
Session
Reason for failure
FCS_NTP_EXT.1 • Configuration of a new
time server
• Removal of configured
time server
Identity if new/removed time
server
FCS_SSHS_EXT.1 Failure to establish an SSH
session
Reason for failure
FCS_TLSC_EXT.1 Failure to establish a TLS
Session
Reason for failure
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 41 of 76
SFR Auditable Event Additional Audit Record
Contents
FCS_TLSS_EXT.1 Failure to establish a TLS
Session
Reason for failure
FIA_X509_EXT.1/Rev • Unsuccessful attempt to
validate a certificate
• Any addition, replacement
or removal of trust anchors
in the TOE's trust store
• Reason for failure of
certificate validation
• Identification of certificates
added, replaced or
removed as trust anchor in
the TOE's trust store
FIA_X509_EXT.2 None None
FIA_X509_EXT.3 None None
FMT_MOF.1/Services None None
FMT_MTD.1/CryptoKeys None None
FMT_MOF.1/Functions None None
6.5.2. FAU_GEN_EXT.1 Security Audit Generation
FAU_GEN_EXT.1.1 The TSF shall be able to generate audit records for each TOE
component. The audit records generated by the TSF of each TOE component shall include
the subset of security relevant audit events which can occur on the TOE component.
6.5.3. FCS_HTTPS_EXT.1 HTTPS Protocol
FCS_HTTPS_EXT.1.1 The TSF shall implement the HTTPS protocol that complies with RFC
2818.
FCS_HTTPS_EXT.1.2 The TSF shall implement HTTPS using TLS.
FCS_HTTPS_EXT.1.3 If a peer certificate is presented, the TSF shall not establish the
connection if the peer certificate is deemed invalid.
6.5.4. FCS_NTP_EXT.1 NTP Protocol
FCS_NTP_EXT.1.1 The TSF shall only use only the following NTP version: [NTP v4 (RFC
5905)].
FCS_NTP_EXT.1.2 The TSF shall update its system time using:
• Authentication using SHA1 as the message digest algorithm(s).
FCS_NTP_EXT.1.3 The TSF shall not update NTP timestamp from broadcast and/or multicast
addresses.
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 42 of 76
FCS_NTP_EXT.1.4 The TSF shall support configuration of at least three (3) NTP time sources
in the Operational Environment.
6.5.5. FCS_SSHS_EXT.1 SSH Server Protocol
FCS_SSHS_EXT.1.1 The TSF shall implement the SSH protocol in accordance with: RFCs
4251, 4252, 4253, 4254, 4256, 4344, 5656, 6668, 8308 section 3.1, 8332.
FCS_SSHS_EXT.1.2 The TSF shall ensure that the SSH protocol implementation supports
the following authentication methods as described in RFC 4252: public key-based, password-
based, no other method.
FCS_SSHS_EXT.1.3 The TSF shall ensure that, as described in RFC 4253, packets greater
than [256K] bytes in an SSH transport connection are dropped.
FCS_SSHS_EXT.1.4 The TSF shall ensure that the SSH transport implementation uses the
following encryption algorithms and rejects all other encryption algorithms: aes128-ctr,
aes256-ctr.
FCS_SSHS_EXT.1.5 The TSF shall ensure that the SSH public-key based authentication
implementation uses ecdsa-sha2-nistp256, ecdsa-sha2-nistp384 and ecdsa-sha2-nistp521 as
its public key algorithm(s) and rejects all other public key algorithms.
FCS_SSHS_EXT.1.6 The TSF shall ensure that the SSH transport implementation uses
hmac-sha2-256, hmac-sha2-512 as its MAC algorithm(s) and rejects all other MAC
algorithm(s).
FCS_SSHS_EXT.1.7 The TSF shall ensure that ecdh-sha2-nistp256 and ecdh-sha2-nistp521
are the only allowed key exchange methods used for the SSH protocol.
FCS_SSHS_EXT.1.8 The TSF shall ensure that within SSH connections, the same session
keys are used for a threshold of no longer than one hour, and each encryption key is used to
protect no more than one gigabyte of data. After any of the thresholds are reached, a rekey
needs to be performed.
6.5.6. FCS_TLSC_EXT.1.1 TLS Client Protocol Without Mutual Authentication
FCS_TLSC_EXT.1.1 The TSF shall implement TLS 1.2 (RFC 5246) and reject all other
TLS and SSL versions. The TLS implementation will support the following ciphersuites:
[selection: (see Table 12)] and no other ciphersuites.
Table 12 TLS Ciphersuites
Ciphersuite Code RFC
TLS_RSA_WITH_AES_128_CBC_SHA256 0x003c RFC 5246
TLS_RSA_WITH_AES_256_CBC_SHA256 0x003d RFC 5246
TLS_RSA_WITH_AES_128_GCM_SHA256 0x009c RFC 5288
TLS_RSA_WITH_AES_256_GCM_SHA384 0x009d RFC 5288
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 43 of 76
Ciphersuite Code RFC
TLS_DHE_RSA_WITH_AES_128_CBC_SHA256 0x0067 RFC 5246
TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 0x006b RFC 5246
TLS_DHE_RSA_WITH_AES_128_GCM_ SHA256 0x009e RFC 5288
TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 0x009f RFC 5288
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256 0xC023 RFC 5289
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384 0xC024 RFC 5289
TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 0xC02B RFC 5289
TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 0xC02C RFC 5289
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 0xc027 RFC 5289
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 0xc028 RFC 5289
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 0xc02f RFC 5289
TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 0xc030 RFC 5289
FCS_TLSC_EXT.1.2 The TSF shall verify that the presented identifier matches the reference
identifier per RFC 6125 section 6.
FCS_TLSC_EXT.1.3 When establishing a trusted channel, by default the TSF shall not
establish a trusted channel if the server certificate is invalid. The TSF shall also
• Not implement any administrator override mechanism.
FCS_TLSC_EXT.1.4 The TSF shall present the Supported Elliptic Curves/Supported Groups
Extension with the following curves/groups: secp256r1, secp384r1 and no other
curves/groups in the Client Hello.
6.5.7. FCS_TLSS_EXT.1 TLS Server Protocol without Mutual Authentication
FCS_TLSS_EXT.1.1 The TSF shall implement TLS 1.2 (RFC 5246) and reject all other TLS
and SSL versions. The TLS implementation will support the following ciphersuites:
(see Table 12) and no other ciphersuites.
FCS_TLSS_EXT.1.2 The TSF shall deny connections from clients requesting SSL 2.0, SSL
3.0, TLS 1.0, and TLS 1.1.
FCS_TLSS_EXT.1.3 The TSF shall perform key establishment for TLS using RSA with key
size 2048 bits, 3072 bits, 4096 bits, Diffie-Hellman parameters with size 2048 bits, 3072 bits,
4096 bits, ECDHE curves secp256r1, secp384r1 and no other curves.
FCS_TLSS_EXT.1.4 The TSF shall support no session resumption.
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 44 of 76
6.5.8. FIA_X509_EXT.1/Rev X.509 Certificate Validation
FIA_X509_EXT.1.1/Rev The TSF shall validate certificates in accordance with the following
rules:
• RFC 5280 certificate validation and certification path validation supporting a minimum
path length of three certificates.
• The certification path must terminate with a trusted CA certificate designated as a trust
anchor.
• The TSF shall validate a certification path by ensuring that all CA certificates in the
certification path contain the basicConstraints extension with the CA flag set to TRUE.
• The TSF shall validate the revocation status of the certificate using the Online
Certificate Status Protocol (OCSP) as specified in RFC 6960, a Certificate Revocation
List (CRL) as specified in RFC 5280 Section 6.3, Certificate Revocation List (CRL) as
specified in RFC 5759 Section 5.
• The TSF shall validate the extendedKeyUsage field according to the following rules:
o Certificates used for trusted updates and executable code integrity verification
shall have the Code Signing purpose (id-kp 3 with OID 1.3.6.1.5.5.7.3.3) in the
extendedKeyUsage field.
o Server certificates presented for TLS shall have the Server Authentication
purpose (id-kp 1 with OID 1.3.6.1.5.5.7.3.1) in the extendedKeyUsage field.
o Client certificates presented for TLS shall have the Client Authentication
purpose (id-kp 2 with OID 1.3.6.1.5.5.7.3.2) in the extendedKeyUsage field.
o OCSP certificates presented for OCSP responses shall have the OCSP
Signing purpose (id-kp 9 with OID 1.3.6.1.5.5.7.3.9) in the
extendedKeyUsage field.
FIA_X509_EXT.1.2/Rev The TSF shall only treat a certificate as a CA certificate if the
basicConstraints extension is present and the CA flag is set to TRUE.
6.5.9. FIA_X509_EXT.2 X.509 Certificate Authentication
FIA_X509_EXT.2.1 The TSF shall use X.509v3 certificates as defined by RFC 5280 to support
authentication for TLS, HTTPS, no other protocols, VVoIP endpoint registration, and no
additional uses.
FIA_X509_EXT.2.2 When the TSF cannot establish a connection to determine the validity of
a certificate, the TSF shall allow the Administrator to choose whether to accept the certificate
in these cases.
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 45 of 76
6.5.10. FIA_X509_EXT.3 X.509 Certificate Requests
FIA_X509_EXT.3.1 The TSF shall generate a Certificate Request as specified by RFC 2986
and be able to provide the following information in the request: public key and device-specific
information, Common Name, Organization, Organizational Unit, Country.
FIA_X509_EXT.3.2 The TSF shall validate the chain of certificates from the Root CA upon
receiving the CA Certificate Response.
6.5.11. FMT_MOF.1/Services Management of Security Functions Behaviour
FMT_MOF.1.1/Services The TSF shall restrict the ability to start and stop the functions
services to Security Administrators.
FMT_MOF.1.1/Functions The TSF shall restrict the ability to modify the behaviour of the
functions transmission of audit data to an external IT entity, handling of audit data, audit
functionality when Local Audit Storage Space is full to Security Administrators.
6.5.12. FMT_MTD.1/CryptoKeys Management of TSF Data
FMT_MTD.1.1/CryptoKeys The TSF shall restrict the ability to manage the cryptographic
keys to Security Administrators.
6.6. MOD_ESC Security Functional Requirements
6.6.1. Auditable events
Table 13 lists the extended auditable events that serve to extend FAU_GEN.1.
Table 13 Extended Auditable Events
SFR Auditable Event Additional Audit Record
Contents
FIA_UAU.2/TC Successful or failed
authentication of trunk
connected network
component
ID of Administrator that
attempts to connect trunk to
external device (if available);
IP-address of device where
trunk request was initiated (if
available);
IP-address of external device
where trunk is to be
connected (if available).
FIA_UAU.2/VVoIP Successful or failed
registration of VVoIP
endpoint/device
ID of Administrator that
attempt to register VVoIP
endpoint to TOE (if available);
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 46 of 76
SFR Auditable Event Additional Audit Record
Contents
IP-address of device where
registration attempt was
initiated (if available);
IP-address of VVoIP endpoint
that attempt to register to
ESC (if available).
FIA_UAU.2/VVoIP Authentication of external
VvoIP endpoint/device
NOTE: Same as above for
FIA_UAU.2/VvoIP.
Authentication of external
VvoIP endpoints must occur
before registration. In short,
no successful registration of
VvoIP endpoint can happen
until after the successful
authentication of the VvoIP
endpoint.
FMT_SMF.1/ESC Modification of TOE Call
Detail Records (CDR)
ID of Administrator attempting
to query or modify database;
IP-address of device where
database query was initiated;
the exact SQL
command/instruction that was
executed.
FMT_SMF.1/ESC Enabling/disabling VVoIP
endpoint/device features
ID of Administrator attempting
to enable/disable service or
feature on ESC or on external
registered device;
IP-address of device where
enabling/disabling of services
or features was initiated;
the feature or service that was
enabled/disabled.
6.6.2. Summary
The MOD_ESC Security Functional Requirements (SFR’s) are specified in this section. The
MOD_ESC SFR’s are summarized in Table 14 below.
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 47 of 76
Table 14 MOD_ESC SFR Summary
Class Name Component
Identification
Component Name
FAU: Security audit FAU_GEN.1/CDR Audit Data Generation - CDR (Call
Detail Record)
FAU_GEN.1/Log Audit Data Generation - Log
(System Log)
FAU_SAR.1/Log Audit Review - Log (System Log)
FAU_STG.1/CDR Protected Audit Trail Storage (Call
Detail Record)
FDP: User data protection FDP_IFC.1 Subset Information Flow Control
FDP_IFF.1 Information Flow Control
Functions
FDP_RIP.1 Subset Residual Information
Protection
FIA: Identification and
authentication
FIA_UAU.2/TC User Authentication before Any
Action - TC (Telecommunications
Devices)
FIA_UAU.2/VVoIP User Authentication before Any
Action - VVoIP (VVoIP Endpoints)
FIA_X509_EXT.2 X.509 Certificate Authentication
(Covered by NDcPP selection)
FMT: Security
management
FMT_CFG_EXT.1 Secure by Default Configuration
FMT_MTD.1 Management of TSF Data
(Covered by NDcPP selection)
FMT_SMF.1 Specification of Management
Functions
(Covered by NDcPP selection)
FMT_SMR.2 Restrictions on Security Roles
(Covered by NDcPP selection)
FPT: Protection of the TSF FPT_FLS.1 Failure with Preservation of a
Secure State
FPT_STM.1 Reliable Time Stamps
FTP: Trusted
path/channels
FTP_ITC.1(1) Inter-TSF Trusted Channel
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 48 of 76
6.6.3. Security Function Requirements
6.6.3.1. FAU_GEN.1/CDR Audit Data Generation (Call Detail Record)
FAU_GEN.1.1/CDR – The TSF shall be able to generate a call detail record (CDR) for
communications between VVoIP endpoints that are established by the TOE.
FAU_GEN.1.2/CDR – The TSF shall record within each CDR at least the following information:
• calling party number (i.e. call originator)
• called party number (i.e. call receiver or terminating number)
• unique transaction sequence number
• call disposition (e.g. call connected, call terminated, call transferred)
• call type (e.g. voice only, voice and video, text)
• call start time
• call end time
• call duration
• unique identifier of the TOE
• call routing into TOE
• call routing out of TOE
• time zone
•
6.6.3.2. FAU_GEN.1/Log Audit Data Generation (System Log)
FAU_GEN.1.1/Log – The TSF shall be able to generate a system log record for current IP
connections, NTP status, CPU usage, memory usage, disk and file storage capacity,
audit storage capacity, power status.
FAU_GEN.1.2/Log – The TSF shall record within each system log record at least the following
information:
a) Date and time of the event, type of event, subject identity (if applicable), and the
outcome (success or failure of the event); and
b) For each audit event type, based on the auditable event definitions of the functional
components included in the PP/ST, [event details described in Table 15].
Table 15 System Event Logs
Event Additional System Log Record Contents
Current IP connections Network interface card (NIC);
Status (up or down).
CPU usage Utilization percentage of TOE CPU(s).
Memory usage Percentage and/or amount of free memory available for use.
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 49 of 76
Event Additional System Log Record Contents
Disk and file storage
capacity
Percentage and/or amount of available space remaining for
each disk or disk partition on the TOE.
Power status (conditional) Status (on or off).
6.6.4. FAU_SAR.1/Log Audit Review (System Log)
FAU_SAR.1.1/Log The TSF shall provide [Security Administrators] with the capability to read
list of audit information from the system log records.
FAU_SAR.1.2/Log The TSF shall provide the system log records in a real-time first-in first-
out scrolling method.
6.6.5. FAU_STG.1/CDR Protected Audit Trail Storage (Call Detail Record)
FAU_STG.1.1/CDR The TSF shall protect the stored call detail records from unauthorized
disclosure and deletion.
FAU_STG.1.2/CDR The TSF shall be able to [prevent] unauthorized modifications to the
stored call detail records.
6.6.6. FAU_VVR_EXT.1 Recording Voice and Video Call Data
FAU_VVR_EXT.1.1 The TSF shall not have the capability to record voice and video call data.
6.6.7. FDP_IFC.1 Subset Information Flow Control
FDP_IFC.1.1 The TSF shall enforce the [enterprise session controller SFP] on [caller-callee
pairs attempting to communicate through the TOE].
6.6.8. FDP_IFF.1 Information Flow Control Functions
FDP_IFF.1.1 The TSF shall enforce the [enterprise session controller SFP] based on the
following types of subject and information security attributes: method by which the TSF
identifies each endpoint for a call using the following call control protocols: SIP and no
other call control protocols.
FDP_IFF.1.2 The TSF shall permit an information flow between a controlled subject and
controlled information via a controlled operation if the following rules hold: [when valid
communication through the TOE is attempted, the TSF will establish a connection between
itself and the caller; the TSF will establish a second connection between itself and the callee;
and the TSF will redirect all communications that it receives between the two endpoints out
through the proper connection].
FDP_IFF.1.3 The TSF shall enforce the [additional information flow control SFP rules: no
additional rules].
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 50 of 76
FDP_IFF.1.4 The TSF shall explicitly authorize an information flow based on the following
rules: [SIP caller registration].
FDP_IFF.1.5 The TSF shall explicitly deny an information flow based on the following rules:
[SIP caller registration].
6.6.9. FDP_RIP.1 Subset Residual Information Protection
FDP_RIP.1.1 The TSF shall ensure that any previous information content of a resource is
made unavailable upon the deallocation of the resource from the following objects: disk
storage location(s) erased by the TSF during factory reset or other wipe operation.
6.6.10. FIA_UAU.2/TC User Authentication before Any Action (Telecommunications
Devices)
FIA_UAU.2.1/TC The TSF shall require each telecommunications device to be successfully
authenticated before allowing any other TSF-mediated actions on behalf of that device.
6.6.11. FIA_UAU.2/VVoIP User Authentication before Any Action (VVoIP Endpoints)
FIA_UAU.2.1/VVoIP The TSF shall require each VVoIP endpoint to be successfully
authenticated before allowing any other TSF-mediated actions on behalf of that endpoint.
6.6.12. FMT_CFG_EXT.1 Secure by Default Configuration
FMT_CFG_EXT.1.1 The TSF shall provide only enough functionality to set new Security
Administrator credentials when configured with default credentials or no credentials.
FMT_CFG_EXT.1.2 The TSF shall be configured by default with permissions which protect it
and its data from unauthorized access.
6.6.13. FMT_SMF.1/ESC Specification of Management Functions (ESC)
FMT_SMF.1.1/ESC The TSF shall be capable of performing the following management
functions:
• Ability to display the real-time connection status of all VVoIP endpoints (hardware and
software) and telecommunications devices;
• Ability to clear all TSF data stored on disk;
• Ability to configure the password policy;
• Ability to specify the set of audited events;
• Ability to configure the behavior of the TOE in response to a self-test failure;
• No other capabilities].
6.6.14. FPT_FLS.1 Failure with Preservation of a Secure State
FPT_FLS.1.1 The TSF shall preserve a secure state through the following means: stop
the main service when the following types of failures occur: [failure of self-tests defined in
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 51 of 76
FPT_TST_EXT.1, failure of hardware components that affect the proper functioning of
the TOE].
6.6.15. FTP_ITC.1/ESC Inter-TSF Trusted Channel (ESC Communications)
FTP_ITC.1.1/ESC The TSF shall be capable of using TLS and no other protocols to
provide a communication channel between itself and another trusted IT product supporting
the following capabilities: VVoIP endpoints (for protection of signaling protocols),
VVoIP endpoints (for protection of voice/video/media content), other ESC devices (for
SIP trunking), no other capabilities that is logically distinct from other communication
channels and provides assured identification of its end points and protection of the channel
data from modification or disclosure.
FTP_ITC.1.2/ESC The TSF shall permit the TSF, another trusted IT product to initiate
communication via the trusted channel.
FTP_ITC.1.3/ESC The TSF shall initiate communication via the trusted channel for other ESC
devices (for SIP trunking).
6.7. TOE Security Functional Requirements Rationale
Table x provides justification for each security objective for the TOE, showing that the SFRs
are suitable to meet and achieve the security objectives.
Table 16 SFT-Objective Rationale
Objective Addressed By Rationale
O.AUTHORIZED_ADMIN
ISTRATION
FAU_STG.1 (refined from Base-
PP)
This SFR supports the objective by
ensuring that stored audit data is
protected from unauthorized access.
FAU_SAR.1/Log This SFR supports the objective by
requiring the TSF to ensure that only
authorized users can view system log
data.
FAU_STG.1/CDR This SFR supports the objective by
requiring the TSF to ensure that only
authorized users can view stored call
detail records.
FMT_CFG_EXT.1 This SFR supports the objective by
defining a secure default configuration
for the TOE so that a user cannot
access the TSF or its data using default
or blank credentials.
FMT_SMF.1/ESC This SFR supports the objective by
defining the authorized management
functions supported by the TOE.
FAU_STG.1/VVR (selection-
based)
This SFR supports the objective by
requiring the TSF to ensure that only
authorized users can access stored
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 52 of 76
Objective Addressed By Rationale
voice/video recordings, if generated by
the TSF.
O.MEDIA_RECORDING FCS_NTP_EXT.1 (refined from
Base-PP)
This SFR supports the objective by
requiring the TSF to support NTP
communications to obtain reliable time
data that is used for accurate recording
of call metadata.
FPT_STM_EXT.1 (refined from
Base-PP)
This SFR supports the objective by
requiring the TSF to synchronize with
an NTP server for reliable time data
that is used for accurate recording of
call metadata.
FAU_GEN.1/CDR This SFR supports the objective by
requiring the TSF to generate call detail
records of VVoIP communications.
FAU_STG.1/CDR This SFR supports the objective by
requiring the TSF to securely store call
detail records.
FAU_VVR_EXT.1 This SFR supports the objective by
allowing the TOE to claim whether or
not it performs voice/video recording of
VVoIP communications.
O.SECURE_VVOIP FCS_DTLSS_EXT.1 (refined
from Base-PP)
This SFR supports the objective by
requiring the use of DTLS to protect
transmitted voice/video media if this is
the chosen method for securing it.
FCS_DTLSS_EXT.2 (refined
from Base-PP)
This SFR supports the objective by
requiring any implementation of DTLS
to use mutual authentication.
FCS_TLSC_EXT.1 (refined
from Base-PP)
This SFR supports the objective by
requiring TLS for SIP and H.323
communications.
FCS_TLSC_EXT.2 (refined
from Base-PP)
This SFR supports the objective by
requiring TLS for SIP and H.323
communications.
FCS_TLSS_EXT.1 (refined
from Base-PP)
This SFR supports the objective by
requiring TLS for SIP and H.323
communications.
FCS_TLSS_EXT.2 (refined
from Base-PP)
This SFR supports the objective by
requiring TLS for SIP and H.323
communications.
FIA_X509_EXT.1/Rev (refined
from Base-PP)
This SFR supports the objective by
requiring X.509 validation in support of
establishing TLS communications.
FIA_X509_EXT.2 (refined from
Base-PP)
This SFR supports the objective by
requiring X.509 authentication in
support of establishing TLS
communications.
FIA_X509_EXT.3 (refined from
Base-PP)
This SFR supports the objective by
requiring the TSF to be able to request
an X.509 certificate that it can present
to external entities when establishing
cryptographic communications.
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 53 of 76
Objective Addressed By Rationale
FPT_STM_EXT.1 (refined from
Base-PP)
This SFR supports the objective by
requiring the TSF to synchronize with
an NTP server for reliable time data
that is used for establishment of valid
cryptographic channels.
FDP_IFC.1 This SFR supports the objective by
defining an enterprise session
controller policy to broker VVoIP
endpoint communications.
FDP_IFF.1 This SFR supports the objective by
defining the rules enforced by the
enterprise session controller policy.
FIA_UAU.2/TC This SFR supports the objective by
requiring authentication of
telecommunications devices that are
connected to the TOE before the TSF
will interact with them.
FIA_UAU.2/VVoIP This SFR supports the objective by
requiring authentication of VVoIP
endpoints that are connected to the
TOE before the TSF will interact with
them.
FTP_ITC.1/ESC This SFR supports the objective by
defining the trusted channels used for
protection of signaling and media data
used in VVoIP and SIP trunking
communications.
FPT_TUD_EXT.1/VVoIP
(implementation-dependent)
This SFR supports the objective by
optionally allowing the TOE to distribute
software/firmware updates to
connected VVoIP endpoints.
O.SELF_PROTECTION FAU_GEN.1/Log This SFR supports the objective by
generating real-time diagnostic activity
for the TOE’s behavior that can be
used to determine if it is experiencing
conditions that could lead to a failure
state.
FDP_RIP.1 This SFR supports the objective by
ensuring the permanent erasure of
residual data so that a
decommissioned or refurbished device
cannot be used to disclose TSF data
without authorization.
FPT_FLS.1 This SFR supports the objective by
ensuring that the TSF enters a secure
failure state if specific hardware or
software failures are detected.
O.SYSTEM_MONITORI
NG
FAU_GEN.1 (refined from
Base-PP)
This SFR supports the objective by
defining additional required auditable
events that are specific to ESC
functionality that extend the audit
generation requirement defined in the
Base-PP.
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 54 of 76
Objective Addressed By Rationale
FAU_STG.1 (refined from Base-
PP)
This SFR supports the objective by
requiring all stored audit data to be
protected against unauthorized access.
FCS_NTP_EXT.1 (refined from
Base-PP)
This SFR supports the objective by
requiring the TSF to support NTP
communications to obtain reliable time
data that is used for accurate recording
of log data.
FPT_STM_EXT.1 (refined from
Base-PP)
This SFR supports the objective by
requiring the TSF to synchronize with
an NTP server for reliable time data
that is used for accurate log data.
FAU_GEN.1/Log This SFR supports the objective by
requiring the TSF to generate a real-
time system log of its own diagnostic
details.
FAU_SAR.1/Log This SFR supports the objective by
defining what users are able to review
the real-time system log.
FAU_SEL.1 (selection-based) This SFR supports the objective by
optionally allowing an administrator to
suppress the generation of certain audit
records.
6.8. TOE MOD_ESC Security Assurance Requirements
The MOD_ESC does not define any additional assurance requirements above and beyond
what is defined in the NDcPP.
7. TOE SUMMARY SPECIFICATIONS
7.1. NDcPP SFR Enforcing Measures
The TOE provides several measures for enforcing the SFR’s. These measures are listed and
briefly described in Table 17 below:
Table 17 NDcPP SFR Enforcing Measures
Measure Description
TOE_Secure_Monitoring The TOE employs the Linux Audit System (auditd) to
log events (see Table 8). All critical event notification
required by the NDcPP and MOD_ESC, including other
useful information from all services running on the
TOE, are configured to output to auditd. The auditd
daemon gets its configuration from
/etc/audit/auditd.conf and its operational rules from
/etc/audit/audit.rules. The audit events and information
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 55 of 76
Measure Description
from each service are configured to a common format
where possible. Secure timestamps (NTP-over-TLS)
are used to guarantee the correct time and date of
each audit entry. TOE_Secure_Monitoring also
provides the ability to detect and report any
unauthorised changes to program and data files. This
is accomplished using the Advanced Intrusion
Detection Environment (AIDE).
TOE_Cryptography All cryptography used by the TOE is implemented in
the OpenSSL library of CCoreV4. The algorithms used
by the TOE are all NIST-approved and FIPS 140-2
validated.
TOE_Secure_Communications Only two methods are used to secure communications
in the TOE – TLS and SSH. Both are secured using
TOE Cryptography. All TLS channels use X.509
certificates and the TOE supports both server
authentication and client authentication (mutual
authentication). Client mutual authentication is only
supported on the SIP server.
TOE_Trusted_Administration The TOE provides a secure administration facility that
can be used remotely via a secure command line shell.
The shell is secured using OpenSSH and the link is
secured using the TOE cryptography. Additional
HTTPS web services (EMP, MY, ECS) allow
management of users, devices, and licences.
TOE_SIP_Server All users of the TOE are registered and authenticated
by the TOE_SIP_Server based on a valid user ID and
password. Voice and Video calls can only be set up
and terminated by the TOE_SIP_Server.
TOE_Secure_Provisioning The TOE_Secure_Provisioning facility manages and
validates all software updates. Software updates are
either digitally signed or based on hash verification.
TOE_Secure_Storage The TOE uses the Operating System’s secure key
store for storing private keys, passwords and other
sensitive data.
Table 18 lists each applicable SFR in the NDcPP and describes the corresponding measures
taken by the TOE to meet the SFRs.
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 56 of 76
Table 18 NDcPP SFR Measures
SFR Measures
FAU_GEN.1 The TOE employs the TOE_Secure_Monitoring facility
which make use of Linux Audit System (auditd) and rsyslog
to log events locally and remotely (see Table 8). The major
services in the TOE are configured to use rsyslog so that all
logs can be centralised and offloaded to a remote audit
server. The Advanced Intrusion Detection Environment
(AIDE) is employed to monitor changes to critical files such
as keys. AIDE detects and logs file changes/deletions and
a cronjob utility is used to detect and log what changed.
Admin login/logout – Logged by the OS via auditd and
rsyslog.
Config changes and what has changed – Logged by
AIDE and a cronjob that detects what changed.
Crypto key changes (key name) – This will be done using
AIDE to detect changes to the file name. All key file names
will reflect the key names.
Admin and user password reset (user name) – Logged
by the OS.
Start/stop of services (App note 2) – Logged by OS and
individual services.
Bad login limit (origin e.g. IP) – Logged by OS/SSHD.
Local login (on machine) – Logged by the OS.
Attempt to manual update TOE – Logged by the OS.
TOE update success/failure – Logged by the OS.
Management of TSF data – Logged by the OS and AIDE
(file changed).
Changes to time/date (origin e.g. IP for successful and
failed attempts, old and new values) – Logged by OS.
Termination of a local session by the session locking
mechanism – OS can timeout idle logins. Set up in
~./bash_profile (e.g. TMOUT=100). This is logged in the
audit log by the OS (USER_LOGOUT).
Termination of an interactive session – SSHD
configured to timeout on idle. This is logged in the audit log
by SSHD (pam_unix(sshd:session): session closed for
user).
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 57 of 76
SFR Measures
Start/stop/fail of trusted channel/path – Logged by
OpenSIPS, OS and SSHD.
FAU_GEN.2 Audit events are linked to source i.e. user/component.
FAU_STG_EXT.1 The TOE consist of a single standalone component that
stores audit data locally and it is capable of securely
transmitting the audit logs to a remote audit server. Uses
Linux auditd configured for real-time remote auditing
(rsyslog) and secured through an STunnel TLS link. Local
audit files are automatically archived numerically in
compressed form after a configurable term (default is
weekly). Each log is archived after reaching a configurable
size (default is 800KB). These archives can be periodically
deleted by the administrator to save disk space as they
would have already been captured by the remote audit
server. A remote log entry is issued when the disk is nearly
full, alerting the administrator to delete the older logs. All
local audit logs are stored in an administrator-protected
directory (/var/log/audit).
FAU_STG_EXT.2 Audit data stored on TOE – Stored in OS-protected
permissioned folders. The audit logs are stored in a
restricted access location requiring the administrator
password.
FAU_STG_EXT.1.3 Truncation of logs – The TOE is a standalone server with
all local logs stored in a specific, restricted directory
(Administrator access only). Local logs are set to automatic
rollover (overwritten) after a configurable term (default is
weekly). However, before being overwritten, the logs are
numerically archived on the TOE in compressed form. The
TOE can save several Gigabytes of local audit logs and this
is dependent on the installed disk size. The TOE logs
rollover with oldest audit logs being overwritten with new
logs. A remote audit server is also used to ensure that no
logs are lost.
FCS_CKM.1 Key gen – RSA 2048 bits, ECC 256/384/521 bits, FFC
schemes using ‘safe-primes’ – uses CCoreV4 for SSH and
TLS cryptography.
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 58 of 76
SFR Measures
FCS_CKM.2 KX – RSA (SP800-56B) – Uses CCoreV4 for SSH and TLS
cryptography. Keys generated according to FCS_CKM.1
ECC (SP800-56A-3) – Uses CCoreV4 for SSH and TLS.
Keys generated according to FCS_CKM.1
DH (RFC 3526 sect. 3) – Uses CCoreV4 for SSH and TLS
cryptography. Keys generated according to FCS_CKM.1
FCS_CKM.4 Key zeroize – Uses CCoreV4 (FIPS 140-2) validated key
destruction method for all ephemeral TLS keys after use.
Ephemeral keys include:
• Pre-master secret
• Session encryption key
• Session integrity key
The TLS server private key is persisted in an OS-protected
permissioned folder and when used in RAM within the FIPS
module is immediately zeroized after use.
TLS client private key is persisted in an OS-protected
permissioned folder and when used in RAM within the FIPS
module is immediately zeroized after use.
SSH public/private key is persisted in an OS-protected
permissioned folder and when used in RAM within the FIPS
module is immediately zeroized after use. All ephemeral
keys that are stored in volatile memory are zeroised by a
single overwrite consisting of zeroes.
The Admin password hash is persisted in an OS-protected
permissioned folder and when used in RAM within the SSH
library is immediately zeroized after use.
For all persistently stored keys, If the key is being replaced
then the exact memory location is overwritten with the new
key.
FCS_COP.1
FCS_COP.1/DataEncryption
FCS_COP.1/SigGen
FCS_COP.1/Hash
FCS_COP.1/KeyedHash
Encryption and decryption: AES 128/256 (CBC, CTR,
GCM) – Uses CCoreV4 (FIPS 140-2).
Signatures:
RSA DSA with key size 2048 bits or greater according to
FIPS PUB 186-4 Section 5.5, using PKCS #1 v2.1 Signature
Schemes RSASSA-PSS and/or RSASSA-PKCS1v1_5;
ISO/IEC 9796-2, Digital signature scheme 2 or Digital
Signature scheme 3,
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 59 of 76
SFR Measures
EC DSA with key sizes of 256 bits or greater according to
FIPS PUB 186-4 Section 6 and Appendix D. Supporting
curves P-256, P-384 and P-521 according to ISO/IEC
14888-3, Section 6.4Hash: SHA2 256/384/512 in byte
mode. Uses CCoreV4 (FIPS 140-2). Output block length
and MAC length is equal to the hash size e.g. 256/384/512
bits according to ISO/IEC 10118-3:2004.
Keyed Hash: Supports HMAC-SHA-256, HMAC-SHA-384
and HMAC-SHA-512 with cryptographic key sizes of 256,
384 and 512 bits. Message digest sizes supported: 256,
384 and 512 bits conforming to ISO/IEC 9797-2:2011,
Section 7 “MAC Algorithm 2”.
FCS_RBG_EXT.1 Random numbers are obtained from the CCoreV4 FIPS
140-2 validated module using CTR_DRBG (AES-256)
method according to ISO18031:2011,SP800-90A.
Additional entropy seeding is provided using the Intel
processor RDSEED instruction.
FCS_RBG_EXT.1.2 Entropy Provided in accordance with ISO/IEC 18031:2011
using CTR_DRBG (AES). The entropy source is the NIST-
compliance Intel processor that supports RDSEED
instruction. Complies with SP 800-90A Rev. 1 and SP 800-
90C (Draft). The entropy strength is 256 bits.
FIA_AFL.1 Password access – Managed by OS PAM module.
Parameters set in /etc/pam.d/system-auth and
/etc/pam.d/password-auth files. SSH based access is
configured for a maximum number of failed login attempts.
The Audit log records all failed logins. Local terminal
access provided in case of admin permanently locked out.
The TOE prevents the offending Administrator from
successfully establishing a remote session using any
authentication method that involves a password until an
Administrator defined time period has elapsed.
FIA_PMG_EXT.1 Passwords shall be composed of upper and lower case
letters, numbers, and the following special characters: “!”,
“@”, “#”, “$”, “%”, “^”, “&”, “*”, “(“, “)”, “[“, “]”, “{“, “}”, “:”, “;”];
Password length shall be configurable to between 9 and 20
characters.
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 60 of 76
SFR Measures
FIA_UIA_EXT.1
FIA_UAU_EXT.2
Administrator access is based on password and SSH
private key, all managed by the SSHD service. The web
services (EMP, MY, ECS) also require a username and
password. The TOE will display a warning banner (SSHD)
and require user identification (OS) and user authentication
(SSHD, OS). A warning banner is provided on the login
pages of EMP, MY, and ECS. All administrators need to be
successfully identified and authenticated before allowing
any other TSF-mediated actions on behalf of that
administrative user.
FIA_UAU.7 No password feedback – OS/SSHD terminal configured
for no password feedback i.e. No echo, no asterisks. The
EMP, MY, and ECS web portals also hide password entry
(displays dots).
FMT_MOF.1 TOE updates restricted – OS restricts TOE updates to
Administrators only.
FMT_MTD.1 TOE management restricted – OS restricts TOE data
management restricted to Administrators only.
“Management” includes (not limited to) create, init, view,
change default, modify, delete, clear and append. Includes
resetting of operator passwords. Admin passwords only
resettable via local terminal access. All admins need to be
successfully identified and authenticated before allowing
any other TSF-mediated actions on behalf of that
administrative user.
FMT_SMF.1 Local and remote administration – enforced with OS and
SSHD.
Access banner – configured with SSHD access banner.
Session inactivity time – Configurable period and session
inactivity time before session termination.
TOE updates verified – update packages are verified by an
administrator by comparing the published hashes.
Display real-time connection status of VVoIP endpoints
(hardware and software) and telecommunications
devices
Displayed using OpenSIPS Control Panel over SSHD.
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 61 of 76
SFR Measures
Configure Auth failure parameters – OS ensures that only
Administrators can configure these parameters.
FMT_SMR.2 Role-based access – Configured in OS.
The TOE maintains the Security Administrator role and the
Administrators can access the TOE locally as well as
remotely.
FPT_SKP_EXT.1 Protected key storage – See TSS for FCS_CKM.4 above.
The TOE prevents reading of all pre-shared keys, symmetric
keys, and private keys.
FPT_APW_EXT.1 Protected password storage – Administrator and operator
password are persisted in OS-protected permissioned
folders only in hash form.
FPT_TST_EXT.1 The following tests are executed by the TOE:
• System Power On Self-Test (POST)
• Cryptography self-test
System POST
When the TOE powers-up, the BIOS and operating system
services perform a Power-On-Self-Text (POST). During the
initial BIOS tests a number of indicators on the TOE
hardware panels indicate the health or failure of several
internal hardware systems e.g. processors, memory, disks,
and Input/Output (I/O) devices. If the TOE does not boot at
all, please consult the hardware manual for information
regarding the status indicators (e.g. LED’s). During the BIOS
POST you can interrupt the server boot-up and view health
logs using the BIOS UEFI System Utilities. When the
operating system boots up the Intelligent Lights Off (iLO)
facility performs an orderly shutdown if a cautionary
temperature level is detected. If the server hardware detects
a critical temperature level before an orderly shutdown
occurs, the server performs an immediate shutdown. Types
of failures include hardware self-test failures (disk/memory
failures). For more details, please consult the AGD.
Cryptography Self-Test
Once the system has booted completely, a Cellcrypt self-test
script is automatically run during the start-up process and
before any services are activated. During the execution of
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 62 of 76
SFR Measures
this script the CCoreV4 FIPS module will test its algorithm
integrity. Failures are recorded in the audit log and the TOE
is rebooted or the service stops working. In case the failure
persists after TOE reboot, the administrator should contact
Cellcrypt Technical Assistance. Types of failures include
cryptography (Known Answer Tests as described in NIST
FIPS 140-2 requirements)).
FPT_TUD_EXT.1 Trusted update (admin only) (hash) – The TOE uses a
hash of the software update files to verify the integrity of
software updates. The hash mechanism ensures that the
software update files have not been modified from the
original files obtained from Cellcrypt. The sha256sum utility
is used for the hash verification and makes use of the FIPS
140-2 validated SHA256 algorithm. The guidance
documentation instructs the administrator of the exact steps
to perform to verify the hash. If the integrity test of the
software package is successful the hash result displays
“OK”, In this case the guidance instructs the administrator to
continue installing the software update. If not, the
administrator is informed to not to install and to contact
Cellcrypt Technical Assistance. Software updates, together
with their hash values can be delivered directly to the
administrator or can be provided on a customer-specific App
Store website only accessible by the administrator based on
name and password.The current version is recorded in the
file /opt/secure/VERSION and is automatically updated with
each software upgrade. The current version can be viewed
by the administrator typing: cat /opt/secure/VERSION. The
software update scripts modify the VERSION file (no
delayed activation). The software update scripts, and update
procedure is described in the AGD
FPT_STM_EXT.1 Reliable timestamp – Managed by OS together with NTP
remote time service.
FTA_SSL_EXT.1 Terminate user session – Administrator console sessions
can be terminated by SSHD; and management sessions
using Cellcrypt Management portals (EMP, MY, ECS) can
be terminated by the portals.
FTA_SSL.3 Inactive session closes after pre-set time – Console
sessions handled by SSHD timeout. Management Portals
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 63 of 76
SFR Measures
can timeout sessions, and all TLS sessions time out after
300s (CCoreV4 default).
FTA_SSL.4 Admin closes session – Administrators can terminate
SSH sessions as well as Management Portal sessions
(EMP, MY, ECS). Admin SSH sessions can be exited by
the Admin and portal web sessions have a “Logout” button.
FTA_TAB.1 Banner display – SSHD displays configurable banner file
and the web portals display a warning on the login screens.
FTP_ITC.1 Trusted channel between TOE and other devices –
Uses TLS and HTTPS for connecting with remote IT
entities. A list of these interfaces are provided below:
Table 19 Inter-TSF and other client interfaces
Service Mode Authentication IT Entity
XMPP Client/Server TLS non-Mutual
Authentication
XMPP Server
API Server HTTPS, TLS
non-Mutual
Authentication
Cellcrypt
Clients for
non-VVoIP
communication
Vault
Aux
Map
Audit Client TLS non-Mutual
Authentication
Audit Server
FTP_TRP.1/Admin Trusted path for administration – Local and remote
access for admins. Uses password for local login according
to FIA_UAU_EXT.2.1 and password and/or key-based auth
for remote login via SSH and HTTPS.
FCS_HTTPS_EXT.1 HTTPS Protocol – Supported by web portals (EMP, MY,
ECS) and using CCoreV4 for the underlying TLS. The web
portals make use of the nginx proxy to provide the HTTPS
protocol in accordance with RFC 2818.
FCS_NTP_EXT.1 NTP Protocol – Uses NTP v4 (RFC 5905). Supported by
the NTP daemon. NTP timestamp authentication uses the
SHA-1 keyed hash method. The implemented method
consists of a local NTP daemon that communicates with
one or more remote authenticated NTP servers to
synchronise the local system clock. The SHA-1 keyed hash
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 64 of 76
SFR Measures
method is compatible with, and has been tested with
NIST’s authenticated NTP servers. The NTP service is
used primarily to provide reliable audit timestamps but also
provides a reliable clock for general system use.
FCS_SSHS_EXT.1 SSH Server Protocol – Supported by OpenSSH using
password-based and public-key based authentication. The
OpenSSH service is configured to only accept users with
the correct SSH private key, and the username and
password is authenticated by the Red Hat Enterprise server
operating system. Successful login allows the administrator
to perform TOE administration through a remote shell
command terminal.
Supported public key algorithms:
• ecdsa-sha2-nistp256
• ecdsa-sha2-nistp384
• ecdsa-sha2-nistp521
Packets larger than 256KB are dropped (RFC 4253). The
TOE uses a 256KB buffer to accumulate the packet
information and checks that the packet has completed
correctly before reaching the end of buffer. If not, the
packet is discarded before being decrypted.
Only the following encryption algorithms are permitted:
• aes128-ctr
• aes256-ctr
Only the following hash algorithms are permitted:
• hmac-sha2-256
• hmac-sha2-512
Only the following key exchange algorithms are permitted:
• ecdh-sha2-nistp256
• ecdh-sha2-nistp521
Session keys valid for no longer than one hour and for no
more than one 1GB of data. Rekey after any of these
thresholds are reached.
Standards compliance:
• For ECDSA schemes: FIPS PUB 186-4, “Digital
Signature Standard (DSS)”, Section 6 and Appendix D,
Implementing “NIST curves” [selection: P-256, P-384, P-
521]; ISO/IEC 14888-3, Section 6.4.
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 65 of 76
SFR Measures
• For Hash schemes: ISO/IEC 10118-3:2004.
• For HMAC schemes: ISO/IEC 9797-2:2011, Section 7
“MAC Algorithm 2”.
FCS_TLSC_EXT.1 Client TLS without mutual authentication – Enforced by
CCoreV4 and supported by services with client TLS
interfaces. Supported ciphersuites listed in Table 12.
The TLS client matches the server X.509 Common Name
(CN) as per RFC 6125 section 6 with allowed hostnames
configured by the administrator in the associated client
configuration file. SAN hostnames and wildcards are
supported but no IP addresses are allowed.
Only the following elliptic curves are supported, and these
must be defined in the client configuration file:
• secp256r1
• secp384r1
FCS_TLSS_EXT.1 Server TLS without mutual authentication – Enforced by
CCoreV4 and supported by services with server TLS and
HTTPS interfaces (EMP, MY, ECS). Supported ciphersuites
listed in Table 12.
Only TLS 1.2 connections are permitted.
RSA 2048/3072/4096 bits, DH 2048/3072/4096 bits.
Only the following ECDHE curves are permitted:
• secp256r1
• secp384r1
The web portals do not require a client certificate and
instead authenticate users using username and password.
The TOE only permits the use of TLS 1.2 with restricted
ciphers (rejects all others). The key agreement parameters
sent by the TOE in the “Server Hello” message are specified
in RFC 5246 (7.4.3) and only the following TLS cipher suites
are permitted:
• TLS_RSA_WITH_AES_128_CBC_SHA256 (RFC 5246)
• TLS_RSA_WITH_AES_256_CBC_SHA256 (RFC 5246)
• TLS_RSA_WITH_AES_128_GCM_SHA256 (RFC 5288)
• TLS_RSA_WITH_AES_256_GCM_SHA384 (RFC 5288)
• TLS_DHE_RSA_WITH_AES_128_CBC_SHA256 (RFC 5246)
• TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 (RFC 5246)
• TLS_DHE_RSA_WITH_AES_128_GCM_ SHA256 (RFC 5288)
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 66 of 76
SFR Measures
• TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 (RFC 5288)
• TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256 (RFC 5289)
• TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384 (RFC 5289)
• TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 (RFC 5289)
• TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 (RFC 5289)
• TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 (RFC 5289)
• TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 (RFC 5289)
• TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (RFC 5289)
• TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (RFC 5289)
No session resumption supported.
FIA_X509_EXT.1/Rev X.509 Certificate Validation - Enforced by CCoreV4 and
supported by services with HTTPS and TLS interfaces.
RFC 5280 certificate and certification path validation
supporting a minimum path length of three certificates.
Certification path terminates with a trusted CA certificate and
all CA certificates must have basicConstraints extension with
CA flag set to TRUE.
Certificates validated using OCSP (RFC 6960, RFC 5280
Section 6.3) and CRL (RFC 5759 Section 5).
For the certificate extendedKeyUsage field the following
rules apply:
• Server TLS certificates must contain the Server
Authentication purpose or else the TOE will refuse
(disconnect) the TLS connection.
• Client TLS certificates must contain the Client
Authentication purpose or else the TOE will refuse
(disconnect) the TLS connection.
• OCSP certificates must contain the OCSP Signing
purpose or else the TOE will refuse (disconnect) the TLS
connection.
Only full server certificate chains are allowed i.e. the server
certificate plus all intermediate CA certificates.
FIA_X509_EXT.2 X.509 Certificate Authentication – Enforced by CCoreV4
and supported by services with HTTPS and TLS interfaces,
including VVoIP endpoint registrations.
Only X.509v3 certificates allowed as defined by RFC 5280.
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 67 of 76
SFR Measures
When the TOE cannot establish a connection to determine
the validity of a certificate, the TOE allows the Administrator
to choose whether to accept the certificate in these cases.
FIA_X509_EXT.3 X.509 Certificate Requests – CSR’s can be requested by
the Administrator using CCoreV4 supported by a script
(“csr-req”) or using OpenSSL commands only within the
private key OS-protected permissioned folder. The device-
specific fields that can be specified by the customer are
included with the csr-req script. The details are specified in
the Acceptance Guidance Document (AGD).
FMT_MOF.1/Services
FMT_MOF.1.1/Functions
FMT_MTD.1/CryptoKeys
Management of Security Functions and TSF data –
Only authorized administrators are permitted to update the
TOE and the TOE does not permit any management
functions to take place prior to login.
Only authorized administrators are permitted to:
• start/stop or configure the following operational services
as described in the guidance:
o OpenSIPS (ESC)
o ntpd
o auditd
o Web portals (EMP, MY, ECS)
o Prosody (XMPP);
• modify parameters affecting the transmission of audit
data to a remote audit server;
• modify the handling of local audit data;
• generate keys;
• import/modify keys and certificates;
• erase keys
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 68 of 76
7.2. MOD_ESC Security Functional Requirement Measures
Table 20 lists each applicable SFR in the MOD_ESC and describes the corresponding
measures taken by the TOE to meet the SFRs.
Table 20 MOD_ESC SFR Measures
SFR Measures
FCS_TLSC_EXT.2 TLS Client Protocol with Authentication – Some interfaces
are configured for TLS client authentication. The client rejects
the connection if the server FQDN does not match the
server’s X.509 certificate Common Name (CN matching).
FCS_TLSS_EXT.2
FCS_TLSS_EXT.2.1
FCS_TLSS_EXT.2.3
TLS Server Protocol with Authentication – The TOE
expects to receive an X.509v3 client certificate as part of the
TLS exchange. The TOE matches the Common Name (CN) in
the client certificate using a pre-configured pattern and rejects
the connection if there is a mismatch. There is no fallback to
username and password and no administrator override to
ignore client certificates.The TOE only permits the use of TLS
1.2 with restricted ciphers (rejects all others). The key
agreement parameters sent by the TOE in the “Server Hello”
message are specified in RFC 5246 (7.4.3) and only the
following TLS cipher suites are permitted:
• TLS_RSA_WITH_AES_128_CBC_SHA256 (RFC 5246)
• TLS_RSA_WITH_AES_256_CBC_SHA256 (RFC 5246)
• TLS_RSA_WITH_AES_128_GCM_SHA256 (RFC 5288)
• TLS_RSA_WITH_AES_256_GCM_SHA384 (RFC 5288)
• TLS_DHE_RSA_WITH_AES_128_CBC_SHA256 (RFC 5246)
• TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 (RFC 5246)
• TLS_DHE_RSA_WITH_AES_128_GCM_ SHA256 (RFC 5288)
• TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 (RFC 5288)
• TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256 (RFC 5289)
• TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384 (RFC 5289)
• TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 (RFC 5289)
• TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 (RFC 5289)
• TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 (RFC 5289)
• TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 (RFC 5289)
• TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (RFC 5289)
• TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (RFC 5289)
FMT_SMF.1/ESC Management of TSF Data - Uses OS access control
features. If more than one admin is required, uses groups to
restrict role. The TOE provides ability to display the real-time
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 69 of 76
SFR Measures
connection status of all VVoIP endpoints (hardware and
software) and telecommunications devices.
Administer TOE locally and remotely and configure
password policy - Locally: using OS with screen and
keyboard. Remotely using SSH-protected shell.
Access Banner – Configured with SSHD in /etc/ssh/sshd-
banner.
Session inactivity time – Uses OpenSIPS setting in
/etc/secure-conf/opensips.cfg.
TOE updates – Using OS package signature verification.
Display real-time status of VVoIP endpoints – Real-time
display in the remote audit log.
Clear disk TSF data – Remote Administration via SSH.
All other configuration – Remote Administration via SSH.
Configure ESC behaviour on self-test fail - Remote
Administration via SSH.
FTP_ITC.1/ESC
FTP_ITC.1.1/ESC
Inter-TSF Trusted Channel - All channels protected using
TLS. OpenSIPS configured for TLS on trunk connections.
The TOE uses TLS for connecting with remote IT entities. A
list of these entities is provided below:
Table 21 Inter-TSF and other client interfaces
Service Mode Authentication IT Entity
SIP Server Client TLS with
Mutual
Authentication
ESC devices (for
SIP trunking)
SIP Server Server TLS with
Mutual
Authentication
VVoIP endpoints
(for protection of
signaling
protocols)
Conferencing
Hub + Media
STUN/Turn
relay
N/A SRTP VVoIP endpoints
(for protection of
voice/video/media
content)
For security details see above measures for:
FCS_TLSC_EXT.2
FCS_TLSS_EXT.2
FCS_TLSS_EXT.2.1
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 70 of 76
SFR Measures
FIA_X509_EXT.2
FIA_X509_EXT.2.2
FTP_ITC.1.2/ESC
FTP_ITC.1/ESC
TSF shall permit TSF or authorized TSF entities to initiate
communication via trusted channel - The TOE allows VVoIP
endpoints such as Cellcrypt Clients to initiate a communication
channel via SIP over mutually authenticated TLS channel to
protect the signalling protocols and VVoIP communication.
FTP_ITC.1.3/ESC TSF shall initiate communication via trusted channel –
The TOE initiates Normal TLS trunk mutually authenticated
connection via OpenSIPS.
FAU_GEN.1/CDR
FAU_GEN.1.1/CDR
FAU_GEN.1.2/CDR
Audit Data Generation (Call Detail Record) – CDR details
logged by OpenSIPS.using OpenSIPS xlog script. The CDR’s
are recorded in the general audit log output and contain the
following fields:
• TOE unique identifier
• Call originator identifier
• Call receiver identifier
• Unique transaction sequence number
• Call status (missed / connected / terminated / failures)
• Call type (voice / voice + video)
• Call start time
• Call end time
• Call duration
• Call direction (incoming / outgoing)
• call routing into TOE
• call routing out of TOE
• Time zone
FAU_GEN.1/Log
FAU_GEN.1.1/Log
FAU_GEN.1.2/Log
Audit Data Generation (System Log) – Logs all items listed
in Table 2 of MOD_ESC. Audit data accumulated from
several services plus the OS itself using syslog.
The System Log records for:
• Current IP connections:
• NTP status
• CPU usage
• Memory usage
• Disk and file storage capacity
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 71 of 76
SFR Measures
• Audit storage capacity
• Power status
The following information can be found in each record:
• Date and time of the event
• Type of event
• Subject identity (if applicable)
• Outcome (success or failure of the event)
See examples in Table 15.
FAU_SAR.1/Log
FAU_SAR.1.1/Log
FAU_SAR.1.2/Log
Audit Review (System Log) – Local log viewed by
Administrator via secure SSH command shell. System is also
configured for remote audit logging using an external audit
server containing larger historical log.
FAU_STG.1/CDR
FAU_STG.1.1/CDR
FAU_STG.1.2/CDR
Protected Audit Trail Storage (Call Detail Record) –
Remote audit server protects all logs including CDR’s and
can only be accessed by authorized Administrators. The
remote audit facility protects CDR’s by moving them off-
machine. This preserves the records even if they
subsequently get deleting/modified on the TOE. Both local
and remote audit trails can only be configured/accessed by
authorized administrators and the remote audit server can be
administrated be separately authorized personnel.
FAU_ VVR_EXT.1 VVoIP recording is Not implemented.
FDP_IFC.1
FDP_IFC.1.1
FDP_IFF.1
FDP_IFF.1.1
FDP_IFF.1.2
Information Flow Control – ESC functionality enforced on
all media communications. All calls managed via the ESC
SIP proxy (OpenSIPS) uses the SIP protocol. The SIP
protocol imposes a central signalling service on all media
communications. All users must establish authorized
connections with other users via the SIP server. All
authorized users are registered in the ESC database and SIP
registration requires a registered username and password
before media communications can take place.
FDP_IFF.1.3 Enforce additional information flow rules – Selection - No
additional rules required.
FDP_IFF.1.4
FDP_IFF.1.5
TSF Explicitly authorize/deny information flow – Handled
by SIP caller registration.
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 72 of 76
SFR Measures
FDP_RIP.1 Subset Residual Information Protection – Disk wipe when
TOE is newly commissioned or when decommissioned. The
entire disk contents are overwritten with ones and zeros
according to NIST SP 800-88 “clear” method.
FIA_UAU.2/TC
FIA_UAU.2.1/TC
User Authentication before Any Action – Only permitted
trunks registered on EMP can establish a session with the
TOE. Uses client-side TLS enabled on the trunk.
FIA_UAU.2/VVoIP
FIA_UAU.2.1/VVoIP
TSF requires VVoIP endpoint authentication – Each
subscriber must first be registered on the EMP database and
each connection to the ESC (SIP REGISTER) enforces ESC
subscriber authentication using TLS client certificates and
requiring the X.509 CN to match the EMP subscriber name.
FMT_CFG_EXT.1
FMT_CFG_EXT.1.1
Secure by Default Configuration - No services can be
started until a real Administrator account has been created.
Assumes that the root user is the Administrator. The TOE will
be delivered with a default Administrator account (unique to
each customer) and the username and password will only be
disclosed to the customer.
FPT_FLS.1
FPT_FLS.1.1
Failure with Preservation of a Secure State – The TOE
performs the following self-tests on start-up:
• System POST.
• Cryptography self-test.
During the BIOS POST any hardware failures will result in the
machine not booting up. When the operating system boots up
the Intelligent Lights Off (iLO) facility performs an orderly
shutdown if a cautionary temperature level is detected. If the
server hardware detects a critical temperature level before an
orderly shutdown occurs, the server performs an immediate
shutdown. A Cellcrypt performs a cryptography self-test
before starting up the normal TOE services and will not allow
any services to start if it detects any cryptography failures. If
the condition persists after rebooting the TOE, call Cellcrypt
Technical Services.
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 73 of 76
7.3. TOE Summary Specification Rationale
TOE_Secure_Audit
TOE_Cryptography
TOE_Secure_Communications
TOE_Trusted_Administration
TOE_SIP_Server
TOE_Secure_Provisioning
TOE_Secure_Storage
FAU_GEN.1 X
FAU_GEN.1/CDR X
FAU_GEN.1/Log X
FAU_GEN.2 X
FAU_STG.1 X
FAU_STG.1/CDR X
FAU_STG_EXT.1 X
FAU_STG_EXT.2 X
FAU_STG_EXT.1.3 X
FAU_SAR.1/Log X
FDP_IFC.1 X
FDP_IFF.1 X
FDP_RIP.1 X
FCS_CKM.1 X
FCS_CKM.2 X
FCS_CKM.4 X
FCS_COP.1 X
FCS_COP.1 X
FCS_RBG_EXT.1 X
FCS_RBG_EXT.1.2 X
FIA_AFL.1 X
FIA_PMG_EXT.1 X
FIA_UIA_EXT.1 X
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 74 of 76
FIA_UAU.7 X
FMT_MOF.1 X
FMT_MTD.1 X
FMT_SMF.1 X
FMT_SMR.2 X
FPT_STM.1 X
FPT_SKP_EXT.1 X
FPT_APW_EXT.1 X
FPT_TST_EXT.1 X
FPT_TUD_EXT.1 X
FPT_STM_EXT.1 X
FTA_SSL_EXT.1 X
FTA_SSL.3 X
FTA_SSL.4 X
FTA_TAB.1 X
FTP_ITC.1 X
FTP_TRP.1/Admin X
FCS_HTTPS_EXT.1 X
FCS_NTP_EXT.1 X
FCS_TLSC_EXT.1 X
FCS_TLSC_EXT.2 X
FCS_TLSS_EXT.1 X
FCS_TLSS_EXT.2 X
FCS_TLSS_EXT.2.1 X
FCS_SSHS_EXT.1 X
FIA_X509_EXT.2 X
FIA_X509_EXT.2.2 X
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 75 of 76
8. ABBREVIATIONS AND ACRONYMS
Table 22 Abbreviations and Acronyms
AEAD Authenticated Encryption with Associated Data
AES Advanced Encryption Standard
CA Certificate Authority
CBC Cipher Block Chaining
CRL Certificate Revocation List
DH Diffie-Hellman
DSA Digital Signature Algorithm
DTLS Datagram Transport Layer Security
ECDH Elliptic Curve Diffie Hellman
ECDSA Elliptic Curve Digital Signature Algorithm
EEPROM Electrically Erasable Programmable Read-Only Memory
FIPS Federal Information Processing Standards
GCM Galois Counter Mode
HMAC Keyed-Hash Message Authentication Code
HTTPS HyperText Transfer Protocol Secure
IP Internet Protocol
IPsec Internet Protocol Security
ND Network Device
NIST National Institute of Standards and Technology
NTP Network Time Protocol
OCSP Online Certificate Status Protocol
PAA Processor Algorithm Accelerators
pND Physical Network Device
POST Power On Self-Test
PP Protection Profile
RBG Random Bit Generator
RSA Rivest Shamir Adleman Algorithm
SD Supporting Document
SHA Secure Hash Algorithm
Cellcrypt Server Security Target ST-FED-SRV-1 v1.0.0
Page 76 of 76
SSH Secure Shell
ST Security Target
TLS Transport Layer Security
TOE Target of Evaluation
TSF TOE Security Functionality
TSS TOE Summary Specification
VPN Virtual Private Network