Vulnerability Discussion

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.

Check

Verify the /run/log/journal and /var/log/journal directories have permissions set to "2640" or less permissive by using the following command:

$ sudo find /run/log/journal /var/log/journal -type d -exec stat -c "%n %a" {} \;
/run/log/journal 2640
/var/log/journal 2640
/var/log/journal/3b018e681c904487b11671b9c1987cce 2640

If any output returned has a permission set greater than "2640", this is a finding.

Verify all files in the /run/log/journal and /var/log/journal directories have permissions set to "640" or less permissive by using the following command:

$ sudo find /run/log/journal /var/log/journal -type f -exec stat -c "%n %a" {} \;
/var/log/journal/3b018e681c904487b11671b9c1987cce/system@99dcc72bb1134aaeae4bf157aa7606f4-0000000000003c7a-0006073f8d1c0fec.journal 640
/var/log/journal/3b018e681c904487b11671b9c1987cce/system.journal 640
/var/log/journal/3b018e681c904487b11671b9c1987cce/user-1000.journal 640
/var/log/journal/3b018e681c904487b11671b9c1987cce/user-1000@bdedf14602ff4081a77dc7a6debc8626-00000000000062a6-00060b4b414b617a.journal 640
/var/log/journal/3b018e681c904487b11671b9c1987cce

If any output returned has a permission set greater than "640", this is a finding.

Fix

Configure Ubuntu 22.04 LTS to set the appropriate permissions to the files and directories used by the systemd journal:

Add or modify the following lines in the "/usr/lib/tmpfiles.d/systemd.conf" file:

z /run/log/journal 2640 root systemd-journal - -
Z /run/log/journal/%m ~2640 root systemd-journal - -
z /var/log/journal 2640 root systemd-journal - -
z /var/log/journal/%m 2640 root systemd-journal - -
z /var/log/journal/%m/system.journal 0640 root systemd-journal - -

Restart the system for the changes to take effect.