1.1.1.6 Ensure mounting of squashfs filesystems is disabled

Information

The squashfs filesystem type is a compressed read-only Linux filesystem embedded in small footprint systems (similar to cramfs). A squashfs image can be used without having to first decompress the image.

Rationale:

Removing support for unneeded filesystem types reduces the local attack surface of the system. If this filesystem type is not needed, disable it.

Solution

Edit or create a file in the /etc/modprobe.d/ directory ending in .conf
Example: /etc/modprobe.d/squashfs.conf
Add the following line:

install squashfs /bin/true

Run the following command to unload the squashfs module:

# rmmod squashfs

See Also

https://workbench.cisecurity.org/files/3148

Item Details

Category: CONFIGURATION MANAGEMENT

References: 800-53|CM-11, CSCv6|13, CSCv7|2.6

Plugin: Unix

Control ID: f492de08f30124c6c0221c6580a40e7786d15e1d4d20f3292c10c99eb049eb2d