RHEL 8 must disable the controller area network (CAN) protocol.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-230495	RHEL-08-040022	SV-230495r792914_rule		Low

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. Failing to disconnect unused protocols can result in a system compromise. The Controller Area Network (CAN) is a serial communications protocol, which was initially developed for automotive and is now also used in marine, industrial, and medical applications. Disabling CAN protects the system against exploitation of any flaws in its implementation.

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. Failing to disconnect unused protocols can result in a system compromise. The Controller Area Network (CAN) is a serial communications protocol, which was initially developed for automotive and is now also used in marine, industrial, and medical applications. Disabling CAN protects the system against exploitation of any flaws in its implementation.

STIG	Date
Red Hat Enterprise Linux 8 Security Technical Implementation Guide	2022-12-06

Details

Check Text ( C-33164r792912_chk )
Verify the operating system disables the ability to load the CAN protocol kernel module. $ sudo grep -r can /etc/modprobe.d/* \| grep "/bin/true" install can /bin/true If the command does not return any output, or the line is commented out, and use of the CAN protocol 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 the CAN protocol. Check to see if the CAN protocol is disabled with the following command: $ sudo grep -r can /etc/modprobe.d/* \| grep "blacklist" blacklist can If the command does not return any output or the output is not "blacklist can", and use of the CAN protocol is not documented with the Information System Security Officer (ISSO) as an operational requirement, this is a finding.

Check Text ( C-33164r792912_chk )

Verify the operating system disables the ability to load the CAN protocol kernel module.

$ sudo grep -r can /etc/modprobe.d/* | grep "/bin/true"

install can /bin/true

If the command does not return any output, or the line is commented out, and use of the CAN protocol 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 the CAN protocol.

Check to see if the CAN protocol is disabled with the following command:

$ sudo grep -r can /etc/modprobe.d/* | grep "blacklist"

blacklist can

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

Fix Text (F-33139r792913_fix)
Configure the operating system to disable the ability to use the CAN protocol kernel module. Add or update the following lines in the file "/etc/modprobe.d/blacklist.conf": install can /bin/true blacklist can Reboot the system for the settings to take effect.