Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module v2.1 FIPS 140-2 Security Policy Version 1.4 Last Update: 2012-10-16 Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module version 2.1 FIPS 140-2 Security Policy Contents 1 Cryptographic Module Specification...................................................................................................................3 1.1 Description of Module ................................................................................................................................3 1.2 Description of Approved Mode....................................................................................................................4 1.3 Cryptographic Module Boundary................................................................................................................5 1.3.1 Hardware Block Diagram ........................................................................................................................6 1.3.2 Software Block Diagram .........................................................................................................................7 1.4 Red Hat Enterprise Linux 6.2 Cryptographic Modules and FIPS 140-2 Certification..................................7 1.4.1 Platforms.................................................................................................................................................. 8 1.4.2 FIPS Approved Mode................................................................................................................................8 2 Cryptographic Module Ports and Interfaces .......................................................................................................9 3 Roles, Services, and Authentication ................................................................................................................10 3.1 Roles........................................................................................................................................................ 10 3.2 Services.................................................................................................................................................... 10 3.2.1 Non-Approved Allowed Services............................................................................................................11 3.3 Operator Authentication............................................................................................................................11 3.4 Mechanism and Strength of Authentication...............................................................................................11 4 Physical Security..............................................................................................................................................12 5 Operational Environment..................................................................................................................................13 5.1 Applicability...............................................................................................................................................13 5.2 Policies..................................................................................................................................................... 13 6 Cryptographic Key Management......................................................................................................................14 6.2 Key Zeroization.........................................................................................................................................15 6.3 Random Number Generation ...................................................................................................................15 7 Electromagnetic Interference/Electromagnetic Compatibility (EMI/EMC) ........................................................16 8 Self Tests ......................................................................................................................................................... 17 8.1 Power-Up Tests........................................................................................................................................17 8.1.1 Software Integrity Test Details ..............................................................................................................17 9 Guidance.......................................................................................................................................................... 18 9.1 Crypto Officer Guidance...........................................................................................................................18 9.1.1 Configuration Changes and FIPS Approved Mode................................................................................19 9.2 User Guidance.......................................................................................................................................... 19 9.3 Handling Self Test Errors .........................................................................................................................19 10 Mitigation of Other Attacks..............................................................................................................................20 11 Glossary and Abbreviations............................................................................................................................21 12 References..................................................................................................................................................... 22 © 2012 Red Hat / atsec information security. This document can be reproduced and distributed only whole and intact, including this copyright notice. 2 of 22 Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module version 2.1 FIPS 140-2 Security Policy 1 Cryptographic Module Specification This document is the non-proprietary security policy for the Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module, and was prepared as part of the requirements for conformance to the Federal Information Processing Standard (FIPS) 140-2, Level 1. The following section describes the module and how it complies with the FIPS 140-2 standard in each of the required areas. 1.1 Description of Module The Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module is a software only, security level 1 cryptographic module, running on a multi-chip standalone platform. The module supplies cryptographic support for the SSH protocol in the Red Hat Enterprise Linux user space. All components of the module will be provided with the software outlined below. The following table shows the overview of the security level for each of the eleven sections of the validation. Security Component Security Level Cryptographic Module Specification 1 Cryptographic Module Ports and Interfaces 1 Roles, Services and Authentication 1 Finite State Model 1 Physical Security N/A Operational Environment 1 Cryptographic Key Management 1 EMI/EMC 1 Self Tests 1 Design Assurance 1 Mitigation of Other Attacks 1 Table 1. Security Level of the Module The module has been tested on the following multi-chip standalone platforms: Manufacturer Model O/S & Ver. HP ProLiant DL585 Red Hat Enterprise Linux 6.2 (Single User Mode) IBM HS22 Red Hat Enterprise Linux 6.2 (Single User Mode) Table 2. Tested Platforms This cryptographic module combines a vertical stack of Linux components intended to limit the external interface each separate component may provide. The list of components and the cryptographic boundary of the composite module is defined as follows: • Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module with the version of the OpenSSH server RPM file of 5.3p1-70.el6. • The configuration of the FIPS mode is provided by the dracut-fips package with the version of the RPM © 2012 Red Hat / atsec information security. This document can be reproduced and distributed only whole and intact, including this copyright notice. 3 of 22 Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module version 2.1 FIPS 140-2 Security Policy file of 004-284.el6_3.1. This RPM version is provided with RHBA:2012-1318 accessible on the Red Hat Network. • The contents of the fipscheck RPM package (version 1.2.0-7.el6). • The contents of the fipscheck-lib RPM package (version 1.2.0-7.el6). 1.2 Description of Approved Mode When in FIPS 140-2 approved mode, the contents of the file /proc/sys/crypto/fips_enabled will be '1'. In Approved mode the module will support the following Approved functions/protocols: ● Triple-DES (Certs. #1226, #1227, #1231 and #1232) ● AES (Certs. #1887, #1888, #1889, #1893, #1894 and #1895), which is implemented in software and also with AES-NI, but only one of these implementations is enabled when the module is loaded ● DSA (Certs. #592, #593, #597 and #598) ● RNG (ANSI X9.31) (Certs. #989, #990, #994 and #995) ● SHA-1, SHA-224, SHA-256, SHA-384, SHA-512: SHS (Certs. #1658, #1659, #1663, #1664) ● HMAC-SHA-1, HMAC-SHA224, HMAC-SHA256, HMAC-SHA384, HMAC-SHA512: HMAC (Certs. #1129, #1130, #1134, #1135) ● RSA (Certs. #964, #965, #969 and #970) The module will support the following Non-Approved functions (see caveat below): ● Diffie-Hellman (see caveat below) ● RSA (encrypt, decrypt) (see caveat below) Note: The Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module will use the Red Hat Enterprise Linux OpenSSL (FIPS 140-2 Validation #1758) Cryptographic Module for standard cryptographic operations and will require that a copy of a FIPS 140-2 level 1 validated version of the Red Hat Enterprise Linux OpenSSL Cryptographic Module be installed on the system for the Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module to operate in a validated mode. The Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module itself implements the SSHv2 protocol. The module should be used with SSHv2 protocol only, as SSHv1 protocol is not supported. The SSHv2 protocol allows the user to specify the HMAC protecting the connection where the module uses HMAC-SHA1. However, the protocol allows specifying the full HMAC SHA1 size of 160 bit as well as using the HMAC-SHA1 which is truncated to the first 96 bits. The integrity check is performed by the Red Hat Enterprise Linux OpenSSL module utility fipscheck using HMAC/SHA256 (Certs. #1129, #1130, #1134 and #1135). The version is 1.2.0-7.el6. CAVEAT: The Module will support the following non-approved algorithms: 1) Diffie-Hellman (key agreement; key establishment methodology provides between 80 and 160 bits of encryption strength) 2) RSA (key wrapping; key establishment methodology provides between 80 and 160 bits of encryption strength) 1.3 Cryptographic Module Boundary The physical module boundary is the surface of the case of the test platform. The logical module boundary is depicted in the software block diagram and is embodied by the SSH server application found at /usr/bin/sshd and the OpenSSL shared library module. © 2012 Red Hat / atsec information security. This document can be reproduced and distributed only whole and intact, including this copyright notice. 4 of 22 Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module version 2.1 FIPS 140-2 Security Policy 1.3.1 Hardware Block Diagram Figure 1. Hardware Block Diagram © 2012 Red Hat / atsec information security. This document can be reproduced and distributed only whole and intact, including this copyright notice. 5 of 22 Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module version 2.1 FIPS 140-2 Security Policy 1.3.2 Software Block Diagram Figure 2. Software Block Diagram 1.4 Red Hat Enterprise Linux 6.2 Cryptographic Modules and FIPS 140-2 Certification A set of kernel cryptographic libraries, services and user level cryptographic applications are certified at FIPS level 1, providing a secure foundation for vendor use in developing dependent services, applications, and even purpose built appliances that may be FIPS certified. The certification is performed at FIPS level 1, a software only certification that does not make any claims about the hardware enclosure. This allows vendors to develop their own higher level FIPS-certified modules using cryptographic modules. The following cryptographic modules are included in the RHEL6.2 certification:  Kernel Crypto API - a software only cryptographic module that provides general-purpose cryptographic services to the remainder of the Linux kernel  Disk Volume Encryption - provides disk management and transparent partial or full disk encryption. Partial disk encryption encrypts only one or more partitions, leaving at least one partition as plaintext.  Libgcrypt- supplies general cryptographic support for the Red Hat Enterprise Linux user space  OpenSSL - a software library supporting FIPS 140-2-approved cryptographic algorithms for general use by vendors  OpenSSH-Server - supplies cryptographic support for the SSH protocol  OpenSSH-Client - supplies cryptographic support for the SSH protocol  Openswan - provides the IKE protocol version 1 key agreement services required for IPSec © 2012 Red Hat / atsec information security. This document can be reproduced and distributed only whole and intact, including this copyright notice. 6 of 22 Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module version 2.1 FIPS 140-2 Security Policy 1.4.1 Platforms The certification was performed on a 64-bit system, which are capable of executing both 32 and 64-bit code concurrently. Vendors can "transfer" the FIPS 140-2 certificate to the other similar platforms, provided the binary is only recompiled without changing the code. This is called a vendor assertion. 1.4.2 FIPS Approved Mode Any vendor-provided FIPS certified cryptographic modules and services that use the RHEL6.2 underlying services to provide cryptographic functionality must use the RHEL6.2 services in their approved mode. The approved mode ensures that FIPS required self tests are executed and that ciphers are restricted to those that have been FIPS 140-2 certified by independent testing. The kernel services (Kernel Crypto API) must be in FIPS approved mode as many services rely on these underlying services for their cryptographic capabilities. See the Kernel Crypto API Security Policy for instructions. If dm-crypt is used to encrypt a disk or partition, particularly when other modules store cryptographic keys or other CSPs (critical security parameters) there, it must be in FIPS approved mode as described in the dm-crypt Security Policy. If the kernel is in the approved mode, the remaining RHEL6.2 FIPS services (libgcrypt, OpenSSL, Openswan, OpenSSH) start up in the approved mode by default. (Note that Openswan uses NSS for its cryptographic operations which must explicitly be put into the approved mode with the modutil command.) The approved mode for a module becomes effective as soon as the module power on self-tests complete successfully and the module loads into memory. Self-tests and integrity tests triggered in RHEL6.2 at start-up or on the first invocation of the crypto module: ● Kernel: during boot, before dm-crypt becomes available via dracut ● User space: before the user space module is available to the caller (i.e., for libraries during the initialization call, for applications: at load time). See each module security policy for descriptions of self tests performed by each module and descriptions of how self test errors are reported for each module. © 2012 Red Hat / atsec information security. This document can be reproduced and distributed only whole and intact, including this copyright notice. 7 of 22 Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module version 2.1 FIPS 140-2 Security Policy 2 Cryptographic Module Ports and Interfaces Function Port Command In Keyboard, Network, Configuration File /etc/ssh/sshd_config, Command Line Options Status Out Display, Network, System Log Data In Host Key Files in /etc/ssh, ~/.ssh/authorized_keys, Network (data via SSHv2 channel, data via local or remote port-forwarding port), locally stored data Data Out Network (data via SSHv2 channel, data via local or remote port-forwarding port), Virtual System Console Table 3. Ports and Interfaces © 2012 Red Hat / atsec information security. This document can be reproduced and distributed only whole and intact, including this copyright notice. 8 of 22 Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module version 2.1 FIPS 140-2 Security Policy 3 Roles, Services, and Authentication This section defines the roles, services, and authentication mechanisms and methods with respect to the applicable FIPS 140-2 requirements. 3.1 Roles Role Services (see list below) User Establish & Maintain SSH Session Close SSH Session (Zeroize) Show Status Crypto Officer Configure SSH Server Establish & Maintain SSH Session Close SSH Session (Zeroize) Terminate SSH Application Self-Tests Show Status Table 4. Roles 3.2 Services The module supports services that are available to users in the various roles. All of the services are described in detail in the module’s user documentation. The following table shows the services available to the various roles and the access to cryptographic keys and CSPs resulting from services. R – The item is read or referenced by the service. W – The item is written or updated by the service. Z – The persistent item is zeroized by the service. All of the ciphers are from the Red Hat Enterprise Linux OpenSSL Cryptographic Module validated cryptographic module. The Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module performs SSH v2 functions only, and passes all cryptographic operations to Red Hat Enterprise Linux OpenSSL Cryptographic Module. Service Category Function Role Cryptographic Keys and CSPs Accessed Access Type (RWZ) Establish & Maintain SSH Session Symmetric Ciphers Encrypt/Decrypt, Keyed-Hash, Key Exchange, Sign/Verify User, Crypto officer RSA or DSA Server private key/public key Client Public Key DH private and public parameters, Session Encryption and Data Authentication Key s DRNG Seed and Seed Key RWZ RW RW © 2012 Red Hat / atsec information security. This document can be reproduced and distributed only whole and intact, including this copyright notice. 9 of 22 Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module version 2.1 FIPS 140-2 Security Policy Service Category Function Role Cryptographic Keys and CSPs Accessed Access Type (RWZ) RW Close SSH Session None Zeroize User, Crypto officer DH private and public parameters, Session Encryption and Data Authentication Keys DRNG Seed and Seed Key Z Terminate SSH Application None Zeroize Crypto officer DH private and public parameters, Session Encryption and Data Authentication Keys DRNG Seed and Seed Key Z Self-Tests Self Test (includes Integrity and known answer tests) Invoked by restarting the module Crypto officer Software Integrity Key R Show Status Status Via verbose mode and exit codes User, Crypto officer None N/A Table 5. Services 3.2.1 Non-Approved Allowed Services In Approved mode, the module will support the following Non-Approved services: ● RSA (encrypt, decrypt) ● Diffie-Hellman (key agreement; key establishment methodology) 3.3 Operator Authentication There is no operator authentication. The assumption of a role is implicit by the action taken. 3.4 Mechanism and Strength of Authentication At security level 1, authentication is not required. © 2012 Red Hat / atsec information security. This document can be reproduced and distributed only whole and intact, including this copyright notice. 10 of 22 Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module version 2.1 FIPS 140-2 Security Policy 4 Physical Security This Module is a security level 1 software module and offers no physical security. © 2012 Red Hat / atsec information security. This document can be reproduced and distributed only whole and intact, including this copyright notice. 11 of 22 Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module version 2.1 FIPS 140-2 Security Policy 5 Operational Environment 5.1 Applicability This module will operate in a modifiable operational environment per the FIPS 140-2 definition. 5.2 Policies The operating system shall be restricted to a single operator mode of operation (i.e., concurrent operators are explicitly excluded). The operator that makes use of the cryptographic module is the single user. In the FIPS approved mode, the ptrace(2) system call, the debugger (gdb(1)) and strace(1) shall not be used. In addition, other tracing mechanisms offered by the Linux environment, such as ftrace or systemtap shall not be used. © 2012 Red Hat / atsec information security. This document can be reproduced and distributed only whole and intact, including this copyright notice. 12 of 22 Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module version 2.1 FIPS 140-2 Security Policy 6 Cryptographic Key Management The following table identifies the Cryptographic Keys and Critical Security Parameters (CSPs) used within the module. Cryptographic keys and CSPs are never output from the module in plaintext. An Approved key generation method is used to generate keys that are generated by the module via OpenSSL. 6.1 Key Life Cycle Table Key Type Generation Establishment Access by Service Entry and Output Method Storage Zeroization Server Private Keys DSA or RSA keys N/A N/A Establish & Maintain SSH Session N/A Plaintext Immediately after use Server Public Keys (not a CSP) DSA or RSA keys N/A N/A Establish & Maintain SSH Session Exported Plaintext N/A Client Public Key DSA or RSA key N/A N/A Establish & Maintain SSH Session Imported Plaintext N/A Session Data Authentication Keys HMAC SHA-1 N/A Established during the SSH handshake through DH. Establish & Maintain SSH Session N/A Ephemeral Close SSH Session or Terminate SSH Application Session Encryption Keys AES or Triple-DES N/A Established during the SSH handshake through DH. Establish & Maintain SSH Session N/A Ephemeral Close SSH Session or Terminate SSH Application Software Integrity Key HMAC SHA-256 N/A N/A Self-Tests N/A Plaintext within the OpenSSL and fipscheck libraries Terminate fipscheck Application Diffie-Hellman Private and Public Parameters DH ANSI X9.31 RNG N/A Establish & Maintain SSH Session N/A Ephemeral Close SSH Session or Terminate SSH Application DRNG Seed 128-bit value N/A N/A Establish & Maintain SSH Session N/A, provided by /dev/uran dom Ephemeral N/A (Termination of the SSH application where OpenSSL zeroizes seed) © 2012 Red Hat / atsec information security. This document can be reproduced and distributed only whole and intact, including this copyright notice. 13 of 22 Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module version 2.1 FIPS 140-2 Security Policy Key Type Generation Establishment Access by Service Entry and Output Method Storage Zeroization DRNG Seed Key 128-bit value N/A N/A Establish & Maintain SSH Session N/A, provided / dev/urand om Ephemeral N/A (Termination of the SSH application where OpenSSL zeroizes key) Table 6. Key Life Cycle Notes: The module ships without containing any keys and CSPs. When the module is configured, the Crypto officer can prevent a man-in-the-middle attack by confirming the user key is correct before storing the key in the .ssh/authorized_keys. Users may also perform this operation only on keys stored in their home directory. The only key management operations during initial configuration include generating the server public-private key pairs. Diffie-Hellman key agreement transpires at the beginning of a session and with sessions after each 1 GB of data transfers or after 1 hour of operation, whichever occurs first. Persistently stored secret and private keys are out of scope, but may be zeroized using the a FIPS140-2 approved mechanism to clear data on hard disks. 6.2 Key Zeroization For volatile memory, memset is included in deallocation operations. There are no restrictions when zeroizing any cryptographic keys and CSPs. 6.3 Random Number Generation A FIPS 140-2, ANSI X9.31 approved pseudo random number generation mechanism will be used in the module, called from OpenSSL, which is seeded by the kernel. The kernel uses /dev/urandom as a source of random numbers for RNG seeds. The Linux kernel initializes this pseudo device at system startup. SSH_USE_STRONG_RNG is a positive integer that must be greater or equal than 6 to be honored. That integer value specifies the number of bytes obtained from /dev/random and mixed into the DRNG state via the OpenSSL RNG RAND_add API call. Further state that this variable can be set in /etc/sysconfig/sshd as this file is sourced by the sshd start script. Please refer to the Red Hat Enterprise Linux – OpenSSL Module v2.0 FIPS 140-2 Security Policy, Section 6.1, “Random Number Generation.” © 2012 Red Hat / atsec information security. This document can be reproduced and distributed only whole and intact, including this copyright notice. 14 of 22 Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module version 2.1 FIPS 140-2 Security Policy 7 Electromagnetic Interference/Electromagnetic Compatibility (EMI/EMC) Product Name and Model: HP ProLiant Server DL585 Series Regulatory Model Number: HSTNS-1025 Product Options: All EMC: Class A Product Name and Model: IBM BladeCenter HS22 Series Regulatory Model Number: 09-EMCRTP-0008 Product Options: All EMC: Class A © 2012 Red Hat / atsec information security. This document can be reproduced and distributed only whole and intact, including this copyright notice. 15 of 22 Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module version 2.1 FIPS 140-2 Security Policy 8 Self Tests FIPS 140-2 requires that the module perform self tests to ensure the integrity of the module and the correctness of the cryptographic functionality at startup. In addition, some functions require continuous verification of function, such as the random number generator. All of these tests are listed and described in this section. 8.1 Power-Up Tests Software Integrity Test - All cryptographic function tests are performed by the Red Hat Enterprise Linux OpenSSL module before it will perform cryptographic operations for the OpenSSH Server module. No operator intervention is required during the running of the self tests. See section 9.3 for descriptions of possible self test errors and recovery procedures. 8.1.1 Software Integrity Test Details OpenSSH userspace modules have their integrity verified at startup by the software integrity test. The integrity check is performed by the Red Hat Enterprise Linux OpenSSL module utility fipscheck using HMAC-SHA256. When the module starts, it exercises the power-on self test, including the software integrity test. The software integrity test (HMAC-SHA256) constitutes a known answer test for the HMAC-SHA256 algorithm. The user space integrity verification is performed as follows: The OpenSSH server application links with the library libfipscheck.so which is intended to execute fipscheck to verify the integrity of the calling application file using HMAC SHA-256. Upon calling the FIPSCHECK_verify() function provided with libfipscheck.so, the fipscheck application is loaded and executed, and the following steps are performed: ● OpenSSL as loaded by fipscheck performs the integrity check of the OpenSSL library files using HMAC SHA-256. ● The application fipscheck performs the integrity check of its application file using HMAC SHA-256 provided by OpenSSL. ● The fipscheck application performs the integrity check of the calling application. The fipscheck computes the HMAC-SHA256 checksum of the file from the command line and compares the computed value to the value stored inside the /path/to/application/..hmac checksum file. The fipscheck application returns the appropriate exit value based on the comparison result (zero if the checksum is OK – which is enforced by the libfipscheck.so library). The fipscheck application also automatically verifies the itegrity of libfipscheck when loaded. © 2012 Red Hat / atsec information security. This document can be reproduced and distributed only whole and intact, including this copyright notice. 16 of 22 Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module version 2.1 FIPS 140-2 Security Policy 9 Guidance NOTE: All cryptographic functions for the Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module will be provided with a copy of a FIPS 140-2 validated version of the Red Hat Open SSL cryptographic module. NOTE: All cryptographic functions for the Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module will be provided by a copy of a FIPS 140-2 validated version of the Red Hat OpenSSL cryptographic module. 9.1 Crypto Officer Guidance The version of the RPMs containing the validated module is stated in section 1, above. The integrity of the RPM is automatically verified during the installation and the Crypto officer shall not install the RPM file if the RPM tool indicates an integrity error. In addition, the OpenSSL FIPS 140-2 module referenced in section 1 must be installed according to its Security Policy. The RPM package of the module can be installed by standard tools recommended for the installation of RPM packages on a Red Hat Enterprise Linux system (for example, yum, rpm, and the RHN remote management tool). For proper operation of the in-module integrity verification, the prelink has to be disabled. This can be done by setting PRELINKING=no in the /etc/sysconfig/prelink configuration file. Existing prelinking, if any, should be undone on all the system files using the 'prelink -u -a' command. To bring the module into FIPS approved mode, perform the following: 1. Install the dracut-fips package: # yum install dracut-fips 2. Recreate the INITRAMFS image: # dracut -f After regenerating the initrd, the crypto officer has to append the following string to the kernel command line by changing the setting in the boot loader: fips=1 If /boot or /boot/efi resides on a separate partition, the kernel parameter boot= must be supplied. The partition can be identified with the command "df /boot" or "df /boot/efi" respectively. For example: $ df /boot Filesystem 1K-blocks Used Available Use% Mounted on /dev/sda1 233191 30454 190296 14% /boot The partition of /boot is located on /dev/sda1 in this example. Therefore, the following string needs to be appended to the kernel command line: "boot=/dev/sda1" Reboot to apply these settings. In addition to the configuration of the kernel, the OpenSSH client configuration ~/.ssh/config should contain:  Either no "Ciphers" option or the option with a subset out of "aes128-ctr, aes192-ctr, aes256-ctr, aes128-cbc, 3des-cbc, aes192-cbc, aes256-cbc" © 2012 Red Hat / atsec information security. This document can be reproduced and distributed only whole and intact, including this copyright notice. 17 of 22 Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module version 2.1 FIPS 140-2 Security Policy  Either no "MACs" option or the option with "hmac-sha1" and/or “hmac-sha1-96”  "Protocol 2" must be specified Reboot to apply these settings. At least one server key pair must be configured before using the module. If the server keys have not been previously set up, the key pairs must be generated by calling ssh-keygen via the start script. To prevent man-in-the-middle attacks, either the relevant public key of the server must be configured in each client connecting to the server, or users operating a SSH client must verify the key fingerprint from a trusted source when connecting to the server. 9.1.1 Configuration Changes and FIPS Approved Mode Use care whenever making configuration changes that could potentially prevent access to the fips_enabled flag (fips=1) in the file /proc. If the module does not detect this flag during initialization, it does not enable the FIPS approved mode. For example, executing the module inside a chroot without the proc file system available, would instantiate the module in non-approved mode. All user space modules depend on this file for transitioning into FIPS approved mode. 9.2 User Guidance Use the 'service sshd start' command to start the OpenSSH server, or configure the server to start using 'chkconfig'. This module is used by connecting to it with a ssh client. See the documentation of the client, e.g., the OpenSSH Client Cryptographic Module security policy and the ssh(1) man page, for more information. 9.3 Handling Self Test Errors OpenSSL self test failures may prevent OpenSSH from operating. See the Guidance section in the OpenSSL Security Policy for instructions on handling OpenSSL self test failures. The OpenSSH self test consists of the software integrity test. If the integrity test fails, OpenSSH enters an error state. The only recovery from this type of failure is to reinstall the OpenSSH module. If you downloaded the software, verify the package hash to confirm a proper download. © 2012 Red Hat / atsec information security. This document can be reproduced and distributed only whole and intact, including this copyright notice. 18 of 22 Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module version 2.1 FIPS 140-2 Security Policy 10 Mitigation of Other Attacks RSA is vulnerable to timing attacks. In a setup where attackers can measure the time of RSA decryption or signature operations, blinding must be used to protect the RSA operation from that attack. The API function of RSA_blinding_on turns blinding on for key rsa and generates a random blinding factor. The random number generator must be seeded prior to calling RSA_blinding_on. Weak Triple-DES keys are detected as follows: /* Weak and semi week keys as taken from * %A D.W. Davies * %A W.L. Price * %T Security for Computer Networks * %I John Wiley & Sons * %D 1984 * Many thanks to smb@ulysses.att.com (Steven Bellovin) for the reference * (and actual cblock values). */ #define NUM_WEAK_KEY 16 static const DES_cblock weak_keys[NUM_WEAK_KEY]={ /* weak keys */ {0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01}, {0xFE,0xFE,0xFE,0xFE,0xFE,0xFE,0xFE,0xFE}, {0x1F,0x1F,0x1F,0x1F,0x0E,0x0E,0x0E,0x0E}, {0xE0,0xE0,0xE0,0xE0,0xF1,0xF1,0xF1,0xF1}, /* semi-weak keys */ {0x01,0xFE,0x01,0xFE,0x01,0xFE,0x01,0xFE}, {0xFE,0x01,0xFE,0x01,0xFE,0x01,0xFE,0x01}, {0x1F,0xE0,0x1F,0xE0,0x0E,0xF1,0x0E,0xF1}, {0xE0,0x1F,0xE0,0x1F,0xF1,0x0E,0xF1,0x0E}, {0x01,0xE0,0x01,0xE0,0x01,0xF1,0x01,0xF1}, {0xE0,0x01,0xE0,0x01,0xF1,0x01,0xF1,0x01}, {0x1F,0xFE,0x1F,0xFE,0x0E,0xFE,0x0E,0xFE}, {0xFE,0x1F,0xFE,0x1F,0xFE,0x0E,0xFE,0x0E}, {0x01,0x1F,0x01,0x1F,0x01,0x0E,0x01,0x0E}, {0x1F,0x01,0x1F,0x01,0x0E,0x01,0x0E,0x01}, {0xE0,0xFE,0xE0,0xFE,0xF1,0xFE,0xF1,0xFE}, {0xFE,0xE0,0xFE,0xE0,0xFE,0xF1,0xFE,0xF1}}; © 2012 Red Hat / atsec information security. This document can be reproduced and distributed only whole and intact, including this copyright notice. 19 of 22 Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module version 2.1 FIPS 140-2 Security Policy Please note that there is no weak key detection by default. The caller can explicitely set the DES_check_key to 1 or call DES_check_key_parity() and/or DES_is_weak_key() functions on its own. © 2012 Red Hat / atsec information security. This document can be reproduced and distributed only whole and intact, including this copyright notice. 20 of 22 Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module version 2.1 FIPS 140-2 Security Policy 11 Glossary and Abbreviations AES Advanced Encryption Specification CAVP Cryptographic Algorithm Validation Program CBC Cypher Block Chaining CCM Counter with Cipher Block Chaining-Message Authentication Code CFB Cypher Feedback CMT Cryptographic Module Testing CMVP Cryptographic Module Validation Program CSP Critical Security Parameter CVT Component Verification Testing DES Data Encryption Standard DH Diffie-Hellman DSA Digital Signature Algorithm ECB Electronic Code Book FSM Finite State Model HMAC Hash Message Authentication Code LDAP Lightweight Directory Application Protocol MAC Message Authentication Code NIST National Institute of Science and Technology NVLAP National Voluntary Laboratory Accreditation Program OFB Output Feedback O/S Operating System RNG Random Number Generator RSA Rivest, Shamir, Addleman SAP Service Access Points SDK Software Development Kit SHA Secure Hash Algorithm SHS Secure Hash Standard SOF Strength of Function SSH Secure Shell TDES Triple DES UI User Interface Table 7, Abbreviations © 2012 Red Hat / atsec information security. This document can be reproduced and distributed only whole and intact, including this copyright notice. 21 of 22 Red Hat Enterprise Linux 6.2 OpenSSH Server Cryptographic Module version 2.1 FIPS 140-2 Security Policy 12 References [1] OpenSSL man pages regarding sshd(8) and sshd_config(5) [2] FIPS 140-2 Standard, http://csrc.nist.gov/groups/STM/cmvp/standards.html [3] FIPS 140-2 Implementation Guidance, http://csrc.nist.gov/groups/STM/cmvp/standards.html [4] FIPS 140-2 Derived Test Requirements, http://csrc.nist.gov/groups/STM/cmvp/standards.html [5] FIPS 197 Advanced Encryption Standard, http://csrc.nist.gov/publications/PubsFIPS.html [6] FIPS 180-3 Secure Hash Standard, http://csrc.nist.gov/publications/PubsFIPS.html [7] FIPS 198-1 The Keyed-Hash Message Authentication Code (HMAC), http://csrc.nist.gov/publications/PubsFIPS.html [8] FIPS 186-3 Digital Signature Standard (DSS), http://csrc.nist.gov/publications/PubsFIPS.html [9] ANSI X9.52:1998 Triple Data Encryption Algorithm Modes of Operation, http://webstore.ansi.org/FindStandards.aspx?Action=displaydept&DeptID=80&Acro=X9&DpName=X9,%20Inc. © 2012 Red Hat / atsec information security. 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