UBTU-18-010121 - The Ubuntu operating system must generate error messages that provide information necessary for corrective actions without revealing information that could be exploited by adversaries.


Any operating system providing too much information in error messages risks compromising the data and security of the structure, and content of error messages needs to be carefully considered by the organization.

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, social security 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.


Configured the Ubuntu operating system to set permissions of all log files under /var/log directory to '640' or more restricted, 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 chmod 640 '{}' ;

See Also


Item Details

References: CAT|II, CCI|CCI-001312, Rule-ID|SV-219188r880865_rule, STIG-ID|UBTU-18-010121, STIG-Legacy|SV-109707, STIG-Legacy|V-100603, Vuln-ID|V-219188

Plugin: Unix

Control ID: 04624a0d9f1a37f802d9120ad346a463c13df8858c6a3a02958f2a4d8edb0504