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1.1.2.2.3 Ensure nosuid option set on /dev/shm partition

Information

The nosuid mount option specifies that the filesystem cannot contain setuid files.

Setting this option on a file system prevents users from introducing privileged programs onto the system and allowing non-root users to execute them.

Solution

- IF - a separate partition exists for /dev/shm.

Edit the /etc/fstab file and add nosuid to the fourth field (mounting options) for the /dev/shm partition. See the fstab(5) manual page for more information.

Example:

tmpfs /dev/shm tmpfs defaults,rw,nosuid,nodev,noexec,relatime 0 0

Run the following command to remount /dev/shm with the configured options:

# mount -o remount /dev/shm

Note: It is recommended to use tmpfs as the device/filesystem type as /dev/shm is used as shared memory space by applications.

Impact:

Setting the nosuid option prevents setuid and setgid bits from taking effect on the /dev/shm filesystem, which is not expected to contain privileged executables; this typically has no operational impact.

See Also

https://workbench.cisecurity.org/benchmarks/27892

Item Details

Category: ACCESS CONTROL, CONFIGURATION MANAGEMENT, MEDIA PROTECTION

References: 800-53|AC-3, 800-53|AC-5, 800-53|AC-6, 800-53|CM-7(2), 800-53|MP-2, CSCv7|14.6

Plugin: Unix

Control ID: 72e334fe00d72180962086612d6441d4ad0183c8a4e134f3b44934dc3e653927