© Copyright 2001 Tumbleweed Communications, Inc.
This document may be freely reproduced and distributed whole and intact including this Copyright Notice.
V1.0
Tumbleweed Messaging Management
System (MMS™) Security Kernel
FIPS 140-1 Non-Proprietary
Security Policy
Level 1 Validation
October, 2000
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Table of Contents
1 INTRODUCTION..............................................................................................................................................3
1.1 Purpose ...........................................................................................................................................................3
1.2 References .......................................................................................................................................................3
1.3 Document Organization ..................................................................................................................................3
2 Tumbleweed MMS.............................................................................................................................................4
2.1 The MMS Security Kernel ...............................................................................................................................4
2.2 Operating System Configuration.....................................................................................................................5
2.3 The MMS Security Kernel API ........................................................................................................................5
2.3.1 User API Calls:......................................................................................................................................5
2.3.2 Crypto Officer API Calls:......................................................................................................................7
2.3.3 Accessing Services ................................................................................................................................8
2.4 Physical Security.............................................................................................................................................8
2.5 Cryptographic Algorithms and Keys...............................................................................................................8
2.6 Self-Tests .........................................................................................................................................................9
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1 INTRODUCTION
1.1 Purpose
This is the non-proprietary FIPS 140-1 security policy for the Tumbleweed Messaging
Management System (MMS™) Security Kernel. This Security Policy details the secure
operation of the MMS Security Kernel as required in Federal Information Processing Standards
Publication 140-1 (FIPS 140-1) as published by the National Institute of Standards and
Technology (NIST) of the United States Department of Commerce.
1.2 References
For more information on the Tumbleweed Messaging Management System, the MMS Security
Kernel, or Tumbleweed’s entire product line, please visit www.tumbleweed.com.
For more information on FIPS 140-1 and validation process, please visit www.FIPS140-1.com.
For more information on NIST and the cryptographic module validation program, please visit
csrc.nist.gov/cryptval
1.3 Document Organization
The Security Policy document is one document in complete FIPS 140-1 Submission Package. In
addition to this document, the complete Submission Package contains:
♦ Vendor Evidence document
♦ Finite State Machine
♦ Module Software Listing
♦ Other supporting documentation as additional references
The remainder of this document (Section 2) outlines the functionality of the module and gives
high-level details on how it meets the requirements of FIPS 140-1. This Security Policy and
other Certification Submission Documentation were produced by Corsec Security, Inc. under
contract to Tumbleweed Communications, Inc. (Tumbleweed). With the exception of this Non-
Proprietary Security Policy, the FIPS 140-1 Certification Submission Documentation is
Tumbleweed-proprietary and is releasable only under appropriate non-disclosure agreements.
For access to these documents, please contact Tumbleweed.
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2 Tumbleweed MMS
The Tumbleweed Messaging Management System (MMSTM
) is a suite of software designed to
allow organizations to apply security beyond the firewall and secure e-mail and Web traffic.
MMS provides a complete set of secure e-mail solutions, including virus scanning, content
control, access control, encryption, and authentication. MMS integrates with existing e-mail
networks and adds secure communications using S-MIME and strong cryptography.
Flexible administration capabilities allow MMS users to secure e-mail configuration with custom
policies across an entire enterprise network. MMS allows administrators and policy-makers to
define and enforce security policies to ensure the safe and efficient use of corporate e-mail
systems. Policies can apply to virus scanning, content control, access control, encryption, and
digital signature policies universally across the enterprise.
A number of subcomponents of MMS provide specific functionality. MMS Content Manager
allows content filtering of e-mail messages and attachments according to set policies. E-mail is
scanned for specific words or content that constitute policy violations. MMS can then block,
quarantine, archive, defer delivery, send to additional recipients, or redirect to alternate
recipients. Content filtering can be combined with Access controls to provide robust protection
against Spam and junk mail, and can be used to block e-mail viruses, such as Melissa.
With MMS Access Manager, companies can set policies that restrict e-mail from certain senders
or to certain recipients. MMS Virus Manager uses integrated server-based anti-virus software
from Network Associates to detect and optionally clean or strip infected attachments in both
incoming and outgoing messages. MMS Format Manager can strip or rewrite addresses in
message headers, protecting your network from potential hackers. The MMS Web Filter
monitors and controls submissions to Internet message boards and Web-based e-mail services,
and includes countermeasures to detect malicious mobile code (Java and ActiveX applets), and
control downloads of inappropriate files and software.
MMS can also enact policies for secure communications by automatically re-routing sensitive e-
mail traffic to Tumbleweed's solution for secure online messaging, Tumbleweed Integrated
Messaging ExchangeTM
(IMETM
). The integrated MMS/IME solution automatically redirects
sensitive traffic to Tumbleweed IMETM
- no end user action is required to send groupware-
generated messages securely over the Internet.
2.1 The MMS Security Kernel
All portions of the MMS use a shared set of cryptographic functionality called the MMS Security
Kernel. The MMS Security Kernel exposes application programming interface API calls to the
other portions of MMS. These APIs allow each sub-component of MMS to access the same
robust, tested security services. These services are also made available to other non-MMS
applications through the Secure Messenger Toolkit (SMT), which includes the MMS Security
Kernel as its Secure Messenger Engine.
The Cryptographic boundary for the MMS Security Kernel encompasses the software contained
within the MMSSMT.DLL. However, for the FIPS 140-1 evaluation, the MMS Security Kernel
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is considered to be a multi-chip standalone cryptographic module running on a standard personal
computer (PC) running the Windows NT operating system in single-user mode. The MMS
Security Kernel can also be run on other Windows and UNIX platforms.
2.2 Operating System Configuration
The MMS Security Kernel was evaluated against all level one requirements of FIPS 140-1 and
the level two operating system requirements, resulting in an overall level 1 FIPS 140-1
validation. The module is installed only as executable code, includes cryptographic self-integrity
checks using FIPS-approved algorithms, and limits access to the executable to authorized users
or processes. The MMS Security Kernel code is written in C and C++ and meets all FIPS 140-1
software security requirements. The module software design corresponds to the Finite State
Machine (FSM) Model described in the Tumbleweed proprietary document: “Tumbleweed
Messaging Management System (MMS™) Security Kernel FIPS 140-1 Finite State Machine”.
The MMS Security Kernel should be securely installed by an administrator of the Windows NT
machine, with permissions to access the module files and directory limited to appropriate
accounts. Using Windows NT to provide this type of controlled access requires the use of the
NTFS file system, and not FAT or FAT32. The administer should limit access to the module to
only users approved to operate the module, and limit access to user data files created by the
module on the hard drive and in SQL tables. User file location is defined during session start.
Access to User data files should be limited to the particular user and the module itself. The
Windows NT User Manager for Domains can be used to define users and groups for whom
access permissions may be defined. The file and folder security properties can then be defined to
specify access for the MMS Security Kernel files.
2.3 The MMS Security Kernel API
The MMS Security Kernel provides a number of services, and supports two distinct roles. These
two roles provide services to configure User information (which is referred to as the Crypto-
Officer role), and to exercise routine User services (which is referred to as the User role). All of
these services are accessed through Applications Programming Interface (API) function calls
described in more detail in the following sections. FIPS 140-1 does not require authentication
for access to services under each role at level 1; however, the MMS Security Kernel provides
some optional User identification capabilities.
Since the MMS Security Kernel is considered a multi-chip standalone module, the physical
interfaces consist of the keyboard, mouse, monitor, serial ports, network adapters, etc. However,
the actual interfaces to the module are the logical inputs through the API and the Graphical User
Interfaces that can be optionally called through the APIs. This includes fifty five active User and
Crypto-Officer function calls, and thirty seven inactive Crypto-Officer function calls (provided
for backwards compatibility purposes). The function calls are divided below into Crypto-Officer
functions and User functions.
2.3.1 User API Calls:
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The User services fall into three groups of API calls. The SMT Message group provides message
manipulation routines, the SMT Session Group provides functions to choose a User and set up an
active User session, and the SMT Util Group provides string conversion utilities.
SMT Session Group (User Services)
SmtSession_Start Start an SMT session
SmtSession_End End an SMT session
SmtSession_CertManager Launch the certificate manager
SmtSession_PickCert Allow selection of a certificate from a list
SmtSession_ViewCert Display a certificate (by SMTID_CERT)
SmtSession_GetCertStatus Gets the status of a certificate
SmtSession_SetProps Set the session properties
SmtSession_GetProps Get the session properties
SmtSession_DisplayProps Display the session properties to the user
SmtSession_GetMaxPageCount (Win32) Propsheet extension support
SmtSession_GetPages (Win32) Propsheet extension support
SmtSession_FreePages (Win32) Propsheet extension support
SmtSession_DetermineBestSigningCertificate Determines the best signing certificate
SmtSession_ExportCert Exports the signing certificate
SmtSession_GenerateProxyCertificate Generates proxy certificate
SmtSession_GetAllUserCertificates Gets signing and proxy certificates
SmtSession_GetCertDetails Get certificate details
SmtSession_GetCertDisplayName Retrieve Certificate and display name
SmtSession_GetProxyCertID Get proxy Certificate Identification
SmtSession_Lock Checks for invalid parameters
SmtSession_IsCertificateSuitableForProxyPar
ent
Check that Certificate is suitable for Proxy
SmtSession_Unlock Retrieve Session Identification
SMT Message Group (User Services)
SmtMsg_Copy Copy contents of one message into another.
SmtMsg_Create Create a new message object
SmtMsg_Destroy Destroy an existing message object
SmtMsg_SetProps Set the message security properties
SmtMsg_GetProps Get the message security properties
SmtMsg_SetSender Set the sender (properties) of a message
SmtMsg_GetSender Get the sender (properties) of a message
SmtMsg_AddRecip Add a recipient to a message
SmtMsg_DeleteRecip Delete a recipient from a message
SmtMsg_BeginEnumRecip Begin enumerating the recipients of a message
SmtMsg_EnumRecip Retrieve the next recipient of a message
SmtMsg_EndEnumRecip End enumerating recipients of a message
SmtMsg_SetRecipProps Set the properties for a recipient
SmtMsg_GetRecipProps Get the properties of a recipient
SmtMsg_ClearPlainBody Clear the plaintext body of a message
SmtMsg_ClearCipherBody Clear the ciphertext body of a message
SmtMsg_BeginWritePlainBody Begin writing the plaintext body of a message
SmtMsg_BeginWriteCipherBody Begin writing the ciphertext body of a message
SmtMsg_WriteBody Write to an open body property of a message
SmtMsg_EndWriteBody End writing to a body property of a message
SmtMsg_BeginReadPlainBody Begin reading the plaintext body of a message
SmtMsg_BeginReadCipherBody Begin reading the ciphertext body of a message
SmtMsg_ReadBody Read from an open body property of a message
SmtMsg_EndReadBody End reading from a body property of a message
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SmtMsg_EncryptAndSign Encrypt and/or sign a message
SmtMsg_DecryptAndVerify Decrypt and/or verify a message signature
SMT Util Group (User Services)
SmtUtil_GetEncAlgorithmStr Converts an encryption algorithm ID to a string
SmtUtil_GetSigAlgorithmStr Converts a signature algorithm ID to a string
2.3.2 Crypto Officer API Calls:
The Crypto Officer calls allow the creation, deletion and modification of Users and their
associated information. This includes user certificates, private keys, addresses, trusts, and other
user configuration data. These may be accessed with the calls in the SMT User Group, and the
optional GUIs that these functions will present. In addition, there is a set of compatibility
functions which may be called but do no processing in this version of the MMS Security Kernel.
These functions return an error value when called in order to indicate that they are only provided
for compatibility purposes.
SMT User Group (Crypto Officer Services)
SmtUser_Add Add a user
SmtUser_GetProps Set the properties of a user
SmtUser_BeginEnum Begin enumerating users
SmtUser_Enum Retrieve the next user
SmtUser_EndEnum End enumerating users
SMT Compatibility Group (Crypto Officer Services)
SmtUser_Delete Delete a user
SmtUser_SetProps Get the properties of a user
SmtUser_DisplayProps Display user properties
SmtUser_DisplayList Display a list of users, returning selected user
SmtUser_DisplayListWithHelp Display users with help, returning selected
SmtAddress_Add Add an entry to the address book
SmtAddress_Delete Delete an entry from the address book
SmtAddress_SetProps Set the properties of an address book entry
SmtAddress_GetProps Get the properties of an address book entry
SmtAddress_DisplayProps Display address book entry properties to user
SmtAddress_BeginEnum Begin enumerating address book entries
SmtAddress_Enum Retrieve the next address book entry
SmtAddress_EndEnum End enumerating address book entries
SmtAddress_DisplayRecipList Displays the recipient list for a message object
SmtAddress_DisplayAddrBook Displays the SMT address book
SmtMsgProp_Display Display message security properties to user
SmtMsgProp_FreePages (Win32) Propsheet extension support
SmtMsgProp_GetMaxPageCount (Win32) Propsheet extension support
SmtMsgProp_GetPages (Win32) Propsheet extension support
SmtMsg_ImportCerts Import Session Identification Certificates
SmtMsg_Publish Publish Session Identification Certificates
SmtSession_AddCertificateSources Add the sources of certificates
SmtSession_ClearPassphrase Clear the private key passphrase
SmtSession_Config Configure Session
SmtSession_DoAbout Display the SMT about box
SmtSession_DoHelp Provide help for a given context
SmtSession_GenerateKey Generate a key pair for the current user
SmtSession_GetCurrentUserAddressKey Retrieve Current Address Key
SmtSession_GetCurrentUserSigningCertificate Retrieve Current Signing Certificate properties
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SmtSession_RegisterCallbacks Register Session ID, UI Parameters, Flags, and
Callbacks
SmtSession_Version Retrieve Session Version
SmtUtil_CheckVersion Performs version checking on SMT
SmtUtil_GetCertStatusStr Converts a certificate status value to a string
SmtUtil_GetRandomData Fills a buffer with random data
SmtUtil_GetSupportedEncAlgorithms Retrieve supported Encryption algorithms
SmtUtil_GetSupportedSigAlgorithms Retrieve supported Signature algorithms
SmtUtil_WipeFile Overwrites and deletes a file
A complete description of each of these functions, including inputs and outputs is provided in the
Tumbleweed MMS SMT Security Kernel Programmers Reference.
2.3.3 Accessing Services
The operators of the module implicitly assume the Crypto Officer or User role when they access
the appropriate API functions for the module. However, before accessing functions, the
operators must create a message or session, and identify themselves to the device as a particular
operator. The evaluated version of the module expects that a single operator is created and
associated with a particular e-mail address. Each user has a set of properties and preferences
associated with them that are used in the generation of messages. Users are selected after the
module has been started and an active session created.
2.4 Physical Security
The MMS Security Kernel is a software module and was tested on the Windows NT operating
system as configured in single-user mode. The MMS Security Kernel module can also be
operated upon other Windows-compatible platforms, but was not tested upon these platforms.
The module was tested against FIPS 140-1 requirements on a standard Intel platform Personal
Computer (PC) that meets all FIPS 140-1 level 1 physical requirements. This includes providing
production grade equipment, standard passivation of components, and FCC certification against
electromagnetic interference and compatibility.
2.5 Cryptographic Algorithms and Keys
The MMS Security Kernel provides a number of cryptographic algorithms, including both FIPS-
approved algorithms and non-FIPS approved algorithms. All FIPS-approved algorithms have
been separately validated as meeting the applicable FIPS standards. The following algorithms
are provided:
FIPS-approved algorithms:
• Data Encryption Standard (DES) (FIPS PUB 46-3) using Cipher Block Chaining
(CBC) mode as defined in NIST Special Publication 800-17
• Triple DES (FIPS PUB 46-3) using CBC mode as defined in NIST Special
Publication 800-20
• Digital Signature Standard (DSS) Digital Signature Algorithm (DSA) (FIPS 186-
2)
• Secure Hashing Algorithm (SHA-1) (FIPS 180-1)
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• RSA Digital Signatures (RSA) (FIPS PUB 186-2) using Public Key
Cryptographic Standard (PKCS) #1 formats. This includes signature generation
and verification using SHA-1 hashing and RSA encryption.
Other algorithms:
• MD5 with RSA Encryption Digital Signatures (Using PKCS#1)
• MD2 with RSA Encryption Digital Signatures (Using PKCS#1)
• MD5 Message Digests
• MD2 Message Digests
• Key Exchange using RSA Public/Private Encryption/Decryption
• RC2 CBC (40, 64, 128, 255 bit) Symmetric Encryption/Decryption
• RC5 (40, 64, 128 bit) Symmetric Encryption/Decryption
Symmetric keys are dynamically created by the module for encryption of messages, and are
zeroized from memory when encryption or decryption operations complete. Symmetric keys are
encrypted using public key technology as defined in SMIME specifications for secure
transmission to recipients.
There are public and private keys managed in the module and associated with each user. Public
keys are included in public key certificates, and stored in SQL tables, and in user specific files.
Private keys are stored internally to the module in private key files, and all of these keys can be
replaced or deleted at the user’s discretion.
2.6 Self-Tests
The MMS Security Kernel consists of software modules running on a Windows NT operating
system in single-user mode, and includes a number of startup and conditional self-tests to ensure
proper operation of the module. This includes a self-integrity check made during software load
using a DSA digital signature of the module, cryptographic algorithm tests, and other critical
startup tests. Additionally, the MMS Security Kernel performs pairwise consistency tests on
newly generated public and private key pairs, and continuous random number generator tests, as
required by FIPS 140-1.