What changed in Canonical Ubuntu 20.04 LTS STIG V2R4V2R4 changes

Canonical Ubuntu 20.04 LTS STIG V2R4 (2025-10-01) replaced V2R3 (2025-07-02): 1 check added, 1 updated. It has 173 checks, against 172 in V2R3.

  • 1 added
  • 0 removed
  • 1 updated

Updated fields: Check text 1Discussion 1

Added in V2R4 (1)

  • V-278950CAT IUbuntu 20.04 LTS must be a vendor-supported release.

Updated in V2R4 (1)

V-238337CAT IIThe Ubuntu operating system must generate error messages that provide information necessary for corrective actions without revealing information that could be exploited by adversaries.Check text, Discussion

Check text

Verify the Ubuntu operating system has all system log files under the "/var/log" directory with a permission set to "640" or less permissive by using the following command: Note: The btmp, wtmp, and lastlog files are excluded. Refer to the Discussion for details. $ sudo find /var/log -perm /137 ! -name '*[bw]tmp' ! -name '*lastlog' -type f -exec stat -c "%n %a" {} 1; If the command displays any output, this is a finding. Note: If output regarding history.log or eipp.log.xz is displayed, this is not a finding.

Discussion

Any operating system providing too much information in error messages risks compromising the data and security of the structure, and contentorganizations ofmust error messages needs to be carefully consideredconsider by the organization.content and Organizations carefully consider the structure/content of error messages. The extent to which information systems are able to identify and handle error conditions is guided by organizational policy and operational requirements. Information that could be exploited by adversaries includes, for example, erroneous logon attempts with passwords entered by mistake as the username, mission/business information that can be derived from (if not stated explicitly by) information recorded, and personal information, such as account numbers, socialSocial securitySecurity numbers, and credit card numbers. The /var/log/btmp, /var/log/wtmp, and /var/log/lastlog files have group write and global read permissions to allow for the lastlog function to perform. Limiting the permissions beyond this configuration will result in the failure of functions that rely on the lastlog database.

How these changes are found

Checks are matched across the two releases by V-number. A check counts as updated when DISA gave it a new rule revision (the r number in its SV-…_rule id) and its title, severity, check text, fix text, discussion, CCIs or other fields changed — the same comparison STIG Compare makes. Added checks are new V-numbers; removed checks are V-numbers V2R4 no longer has.

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