Title

All files and directories contained in user home directories must be group-owned by a group of which the home directorys owner is a member. (Cat II impact)

Discussion

If a user's files are group-owned by a group of which the user is not a member, unintended users may be able to access them.

Check Content

Check the contents of user home directories for files group-owned by a group of which the home directory's owner is not a member. 1. List the user accounts. # cut -d : -f 1 /etc/passwd 2. For each user account, get a list of GIDs for files in the user's home directory. # find ~username -printf %G\\n | sort | uniq 3. Obtain the list of GIDs where the user is a member. # id -G username 4. Check the GID lists. If there are GIDs in the file list not present in the user list, this is a finding.

Fix Text

Change the group of a file not group-owned by a group of which the home directory's owner is a member. # chgrp <group with user as member> <file with bad group ownership> Document all changes.

Additional Identifiers

Rule ID: SV-45038r1_rule

Vulnerability ID: V-22351

Group Title: GEN001550

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.