Rule version BCAS-ND-001980 · STIG v1 · 2026-09-16
Password-based authentication applies to passwords regardless of whether they are used in single-factor or multifactor authentication. Long passwords or passphrases are preferable over shorter passwords. Enforced composition rules provide marginal security benefits while decreasing usability. However, organizations may choose to establish certain rules for password generation (e.g., minimum character length for long passwords) under certain circumstances and can enforce this requirement in IA-5(1)(h). Account recovery can occur, for example, in situations when a password is forgotten. Cryptographically protected passwords include salted one-way cryptographic hashes of passwords. The list of commonly used, compromised, or expected passwords includes passwords obtained from previous breach corpuses, dictionary words, repetitive or sequential characters, and default manufacturer passwords. The list includes context-specific words, such as the name of the service, username, and derivatives thereof.
Verify "prohibit-common-words" is set to "built-in" with the following steps:
1. Log on to the SSH CLI with an administrative account. 2. Enter "show running-config authentication password-policy". 3. Review the output for the common words restriction setting.
If "prohibit-common-words" does not display "built-in", or the setting is missing, this is a finding.
Configure password "prohibit-common-words" to "built-in" with the following steps:
1. Log on to the SSH CLI with an administrative account. 2. Enter "enable" and provide the password. 3. Enter "configure terminal". 4. Enforce the built-in dictionary check by entering "authentication password-policy prohibit-common-words built-in". 5. Enter "exit" to return to the config context, and then enter "exit" again to leave configuration mode.