Title

Removable media, remote file systems, and any file system that does not contain approved setuid files must be mounted with the "nosuid" option. (Cat II impact)

Discussion

The "nosuid" mount option causes the system to not execute setuid files with owner privileges. This option must be used for mounting any file system that does not contain approved setuid files. Executing setuid files from untrusted file systems, or file systems that do not contain approved setuid files, increases the opportunity for unprivileged users to attain unauthorized administrative access.

Check Content

Check /etc/vfstab and verify the "nosuid" mount option is used on any user filesystem (such as /export/home) or filesystems mounted from removable media or network shares. # cat /etc/vfstab Check zfs filesystems for setuid mounts. #zfs get setuid

Fix Text

Use the following procedure for UFS filesystems. Edit /etc/vfstab and add the "nosuid" mount option to any user filesystem (such as /export/home) or filesystems mounted from removable media or network shares. Use the following procedure for ZFS filesystems. # zfs setuid = off < file system >

Additional Identifiers

Rule ID: SV-220089r854459_rule

Vulnerability ID: V-220089

Group Title: SRG-OS-000368

Expert Comments

CCIs tied to check.

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