AlmaLinux OS 9 must disable the Controller Area Network (CAN) kernel module.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-269343	SRG-OS-000095-GPOS-00049	ALMA-09-029830	SV-269343r1050225_rule	2025-02-20	1

Description
The CAN protocol is a robust vehicle bus standard designed to allow microcontrollers and devices to communicate with each other's applications without a host computer. Disabling CAN protects the system against exploitation of any flaws in its implementation.

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

ℹ️ Check

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

✔️ Fix
To configure the system to prevent the can kernel module from being loaded, run the following command: $ cat << EOF \| tee /etc/modprobe.d/can.conf install can /bin/false blacklist can EOF