Vulnerability Discussion

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.

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