Title

File systems that contain user home directories must be mounted to prevent files with the setuid and setguid bit set from being executed. (Cat II impact)

Discussion

The "nosuid" mount option causes the system to not execute setuid and setgid files with owner privileges. This option must be used for mounting any file system not containing approved setuid and setguid files. Executing files from untrusted file systems increases the opportunity for unprivileged users to attain unauthorized administrative access.

Check Content

Verify file systems that contain user home directories are mounted with the "nosuid" option. Note: If a separate file system has not been created for the user home directories (user home directories are mounted under "/"), this is not a finding as the "nosuid" option cannot be used on the "/" system. Find the file system(s) that contain the user home directories with the following command: # awk -F: '($3>=1000)&&($1!="nobody"){print $1,$3,$6}' /etc/passwd smithj:1001: /home/smithj robinst:1002: /home/robinst Check the file systems that are mounted at boot time with the following command: # more /etc/fstab UUID=a411dc99-f2a1-4c87-9e05-184977be8539 /home ext4 rw,relatime,discard,data=ordered,nosuid 0 2 If a file system found in "/etc/fstab" refers to the user home directory file system and it does not have the "nosuid" option set, this is a finding.

Fix Text

Configure the "/etc/fstab" to use the "nosuid" option on file systems that contain user home directories for interactive users.

Additional Identifiers

Rule ID: SV-215012r610931_rule

Vulnerability ID: V-215012

Group Title: SRG-OS-000480-GPOS-00227

Expert Comments

CCIs tied to check.

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