1.1.17 Ensure noexec option set on /dev/shm partition

Information

The noexec mount option specifies that the filesystem cannot contain executable binaries.

Rationale:

Setting this option on a file system prevents users from executing programs from shared memory. This deters users from introducing potentially malicious software on the system.

Solution

Edit the /etc/fstab file and add noexec to the fourth field (mounting options) for the /dev/shm partition. See the fstab(5) manual page for more information.
Run the following command to remount /dev/shm:

# mount -o remount,noexec /dev/shm

Notes:

The setting in /etc/default/rcS, if present, will still be used, but the setting in /etc/default/tmpfs will take precedence if enabled. If desired, the defaults may also be overridden with an entry in in /etc/fstab

/run/shm was previously /dev/shm, and a compatibility symlink or bind mount will be created to allow the old path to continue to function. If an fstab entry for /dev/shm exists instead of /run/shm, then /dev/shm will continue to be used.

See Also

https://workbench.cisecurity.org/files/2658

Item Details

Category: CONFIGURATION MANAGEMENT

References: 800-53|CM-11, CSCv7|2.6

Plugin: Unix

Control ID: e18eddfa5029e5dbc6294a9caad577db764f32d40c096d68280c8f5e1223ed18