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CIS Ubuntu 14.04 LTS - 5.3.3 Ensure password reuse is limited

DevOps & Security
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Verify PAM is configured to remember at least 5 previous passwords to prevent reuse

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Source SKILL.md: https://github.com/CyberStrikeus/CyberStrike/blob/HEAD/.cyberstrike/skill/CIS_benchmarks/Operating_Systems/Ubuntu/CIS_Ubuntu_Linux_14.04_LTS_Benchmark_v2.1.0/cis-ubuntu1404-v210-5-3-3/SKILL.md

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5.3.3 Ensure password reuse is limited (Scored)

Profile Applicability

  • Level 1 - Server
  • Level 1 - Workstation

Description

The /etc/security/opasswd file stores the users' old passwords and can be checked to ensure that users are not recycling recent passwords.

Rationale

Forcing users not to reuse their past 5 passwords make it less likely that an attacker will be able to guess the password.

Note that these change only apply to accounts configured on the local system.

Audit Procedure

Run the following commands and ensure the remember option is '5' or more and included in all results:

egrep '^password\s+required\s+pam_pwhistory.so' /etc/pam.d/common-password

Expected Result

password required pam_pwhistory.so remember=5

Remediation

Edit the /etc/pam.d/common-password file to include the remember option and conform to site policy as shown:

password required pam_pwhistory.so remember=5

Default Value

No password reuse limit configured by default.

References

  • CIS Controls: 16 - Account Monitoring and Control

Profile

  • Level 1 - Server
  • Level 1 - Workstation