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 the operating system disables the ability to load the "can" kernel module.

$ sudo grep -r can /etc/modprobe.d/* | grep -i "/bin/false" | grep -v "^#"
install can /bin/false

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.

Verify the operating system disables the ability to use CAN with the following command:

$ sudo grep can /etc/modprobe.d/* | grep -i "blacklist" | grep -v "^#"
blacklist can

If the command does not return any output or the output is not "blacklist can", and use of CAN is not documented with the ISSO as an operational requirement, this is a finding.

Fix

Configure OL 8 to disable the ability to use the "can" kernel module.

Create a file under "/etc/modprobe.d" with the following command:

$ sudo touch /etc/modprobe.d/can.conf

Add the following line to the created file:

install can /bin/false

Configure OL 8 to disable the ability to use the can kernel module.

$ sudo vi /etc/modprobe.d/blacklist.conf

Add or update the line:

blacklist can