cyberstrikeus 2.23 Disable Mounting of squashfs Filesystems (Not Scored)
Profile Applicability
- Level 2
Description
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 server. If this filesystem type is not needed, disable it.
Audit Procedure
Using Command Line
/sbin/modprobe -n -v squashfs
/sbin/lsmod | grep squashfs
Expected Result
The first command should output install /bin/true. The second command should produce no output (module not loaded).
Remediation
Using Command Line
Edit or create the file /etc/modprobe.d/CIS.conf and add the following line:
install squashfs /bin/true
Default Value
By default, the squashfs module is available for loading.
References
- CIS Ubuntu 12.04 LTS Server Benchmark v1.1.0
Profile
Level 2 - Not Scored