cyberstrikeus 2.15 Add nosuid Option to /run/shm Partition (Scored)
Profile Applicability
- Level 1
Description
The nosuid mount option specifies that the /run/shm (temporary filesystem stored in memory) will not execute setuid and setgid on executable programs as such, but rather execute them with the uid and gid of the user executing the program.
Rationale
Setting this option on a file system prevents users from introducing privileged programs onto the system and allowing non-root users to execute them.
Audit Procedure
Using Command Line
grep /run/shm /etc/fstab | grep nosuid
mount | grep /run/shm | grep nosuid
Expected Result
Both commands should return output showing nosuid is set. If either command emits no output then the system is not configured as recommended.
Remediation
Using Command Line
Edit the /etc/fstab file and add nosuid to the fourth field (mounting options). Look for entries that have mount points that contain /run/shm. See the fstab(5) manual page for more information.
mount -o remount,nosuid /run/shm
Default Value
By default, the nosuid option is not set on the /run/shm partition.
References
- CIS Ubuntu 12.04 LTS Server Benchmark v1.1.0
Profile
Level 1 - Scored