ALMA-09-030160 - AlmaLinux OS 9 must disable mounting of squashfs.

Information

Removing support for unneeded filesystem types reduces the local attack surface of the server.

A squashfs compressed filesystem image can be mounted without first decompressing the image.

Note that Snap packages use squashfs.

Solution

To configure the system to prevent the squashfs kernel module from being loaded, create a *.conf file in /etc/modprobe.d/ with the following content:

install squashfs /bin/false
blacklist squashfs

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_CL_AlmaLinux_OS_9_V1R2_STIG.zip

Item Details

Category: CONFIGURATION MANAGEMENT

References: 800-53|CM-7a., CAT|II, CCI|CCI-000381, Rule-ID|SV-269346r1050228_rule, STIG-ID|ALMA-09-030160, Vuln-ID|V-269346

Plugin: Unix

Control ID: c160ca8c95e187c0f65cfd0a7cac75b3dafb19cb3d22d34326ce493209ebeced