OL 9 must disable mounting of cramfs.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
low	V-271448	SRG-OS-000095-GPOS-00049	OL09-00-000045	SV-271448r1155297_rule	2025-12-22	1

Description
It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Removing support for unneeded filesystem types reduces the local attack surface of the server. Compressed ROM/RAM file system (or cramfs) is a read-only file system designed for simplicity and space-efficiency. It is mainly used in embedded and small-footprint systems.

Description

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities or services are often overlooked and therefore may remain unsecured. They increase the risk to the platform by providing additional attack vectors. Removing support for unneeded filesystem types reduces the local attack surface of the server. Compressed ROM/RAM file system (or cramfs) is a read-only file system designed for simplicity and space-efficiency. It is mainly used in embedded and small-footprint systems.

ℹ️ Check
Verify OL 9 disables the ability to load the cramfs kernel module with the following command: $ grep -irs cramfs /etc/modprobe.conf /etc/modprobe.d/* /etc/modprobe.d/blacklist.conf:install cramfs /bin/false /etc/modprobe.d/blacklist.conf:blacklist cramfs If the command does not return any output, or the line is commented out, and use of the cramfs protocol is not documented with the information system security officer (ISSO) as an operational requirement, this is a finding.

ℹ️ Check

Verify OL 9 disables the ability to load the cramfs kernel module with the following command: $ grep -irs cramfs /etc/modprobe.conf /etc/modprobe.d/* /etc/modprobe.d/blacklist.conf:install cramfs /bin/false /etc/modprobe.d/blacklist.conf:blacklist cramfs If the command does not return any output, or the line is commented out, and use of the cramfs protocol is not documented with the information system security officer (ISSO) as an operational requirement, this is a finding.

✔️ Fix
Configure OL 9 to prevent the cramfs kernel module from being loaded. Add the following line to the file /etc/modprobe.d/cramfs.conf (or create blacklist.conf if it does not exist): install cramfs /bin/false blacklist cramfs Reboot the system for the settings to take effect.