The system must use a FIPS 140-2 approved cryptographic hashing algorithm for generating account password hashes (system-auth).

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-38574	RHEL-06-000062	SV-50375r4_rule		Medium

Description
Using a stronger hashing algorithm makes password cracking attacks more difficult.

STIG	Date
Red Hat Enterprise Linux 6 Security Technical Implementation Guide	2018-03-01

Details

Check Text ( C-46132r5_chk )
Inspect the "password" section of "/etc/pam.d/system-auth", "/etc/pam.d/system-auth-ac", "/etc/pam.d/password-auth", "/etc/pam.d/password-auth-ac" and other files in "/etc/pam.d" to identify the number of occurrences where the “pam_unix.so” module is used in the “password” section. $ grep -E -c 'password.pam_unix.so' /etc/pam.d/ /etc/pam.d/atd:0 /etc/pam.d/config-util:0 /etc/pam.d/crond:0 /etc/pam.d/login:0 /etc/pam.d/other:0 /etc/pam.d/passwd:0 /etc/pam.d/password-auth:1 /etc/pam.d/password-auth-ac:1 /etc/pam.d/sshd:0 /etc/pam.d/su:0 /etc/pam.d/sudo:0 /etc/pam.d/system-auth:1 /etc/pam.d/system-auth-ac:1 /etc/pam.d/vlock:0 Note: The number adjacent to the file name indicates how many occurrences of the “pam_unix.so” module are found in the password section. If the “pam_unix.so” module is not defined in the “password” section of “/etc/pam.d/system-auth”, “/etc/pam.d/system-auth-ac”, “/etc/pam.d/password-auth”, and “/etc/pam.d/password-auth-ac” at a minimum, this is a finding. Verify that the “sha512” variable is used with each instance of the “pam_unix.so” module in the “password” section: $ grep password /etc/pam.d/* \| grep pam_unix.so \| grep sha512 /etc/pam.d/password-auth:password sufficient pam_unix.so sha512 [other arguments…] /etc/pam.d/password-auth-ac:password sufficient pam_unix.so sha512 [other arguments…] /etc/pam.d/system-auth:password sufficient pam_unix.so sha512 [other arguments…] /etc/pam.d/system-auth-ac:password sufficient pam_unix.so sha512 [other arguments…] If this list of files does not coincide with the previous command, this is a finding. If any of the identified “pam_unix.so” modules do not use the “sha512” variable, this is a finding.

Check Text ( C-46132r5_chk )

Inspect the "password" section of "/etc/pam.d/system-auth", "/etc/pam.d/system-auth-ac", "/etc/pam.d/password-auth", "/etc/pam.d/password-auth-ac" and other files in "/etc/pam.d" to identify the number of occurrences where the “pam_unix.so” module is used in the “password” section.

$ grep -E -c 'password.*pam_unix.so' /etc/pam.d/*

/etc/pam.d/atd:0
/etc/pam.d/config-util:0
/etc/pam.d/crond:0
/etc/pam.d/login:0
/etc/pam.d/other:0
/etc/pam.d/passwd:0
/etc/pam.d/password-auth:1
/etc/pam.d/password-auth-ac:1
/etc/pam.d/sshd:0
/etc/pam.d/su:0
/etc/pam.d/sudo:0
/etc/pam.d/system-auth:1
/etc/pam.d/system-auth-ac:1
/etc/pam.d/vlock:0

Note: The number adjacent to the file name indicates how many occurrences of the “pam_unix.so” module are found in the password section.

If the “pam_unix.so” module is not defined in the “password” section of “/etc/pam.d/system-auth”, “/etc/pam.d/system-auth-ac”, “/etc/pam.d/password-auth”, and “/etc/pam.d/password-auth-ac” at a minimum, this is a finding.

Verify that the “sha512” variable is used with each instance of the “pam_unix.so” module in the “password” section:

$ grep password /etc/pam.d/* | grep pam_unix.so | grep sha512

/etc/pam.d/password-auth:password sufficient pam_unix.so sha512 [other arguments…]
/etc/pam.d/password-auth-ac:password sufficient pam_unix.so sha512 [other arguments…]
/etc/pam.d/system-auth:password sufficient pam_unix.so sha512 [other arguments…]
/etc/pam.d/system-auth-ac:password sufficient pam_unix.so sha512 [other arguments…]

If this list of files does not coincide with the previous command, this is a finding.

If any of the identified “pam_unix.so” modules do not use the “sha512” variable, this is a finding.

Fix Text (F-43522r4_fix)
In "/etc/pam.d/system-auth”, "/etc/pam.d/system-auth-ac", “/etc/pam.d/password-auth”, and “/etc/pam.d/password-auth-ac”, among potentially other files, the "password" section of the files controls which PAM modules execute during a password change. Set the "pam_unix.so" module in the "password" section to include the argument "sha512", as shown below: password sufficient pam_unix.so sha512 [other arguments...] This will help ensure when local users change their passwords, hashes for the new passwords will be generated using the SHA-512 algorithm. This is the default. Note: Any updates made to "/etc/pam.d/system-auth" will be overwritten by the "authconfig" program. The "authconfig" program should not be used.

Fix Text (F-43522r4_fix)

In "/etc/pam.d/system-auth”, "/etc/pam.d/system-auth-ac", “/etc/pam.d/password-auth”, and “/etc/pam.d/password-auth-ac”, among potentially other files, the "password" section of the files controls which PAM modules execute during a password change. Set the "pam_unix.so" module in the "password" section to include the argument "sha512", as shown below:

password sufficient pam_unix.so sha512 [other arguments...]

This will help ensure when local users change their passwords, hashes for the new passwords will be generated using the SHA-512 algorithm. This is the default.

Note: Any updates made to "/etc/pam.d/system-auth" will be overwritten by the "authconfig" program. The "authconfig" program should not be used.