The system must not be configured for network bridging.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-22421	GEN003619	SV-45738r1_rule		Medium

Description
Some systems have the ability to bridge or switch frames (link-layer forwarding) between multiple interfaces. This can be useful in a variety of situations but, if enabled when not needed, has the potential to bypass network partitioning and security.

STIG	Date
SUSE Linux Enterprise Server v11 for System z Security Technical Implementation Guide	2018-09-19

Details

Check Text ( C-43101r1_chk )
Verify the system is not configured for bridging. # ls /proc/sys/net/bridge If the directory exists, this is a finding. # lsmod | grep '^bridge ' If any results are returned, this is a finding.

Fix Text (F-39138r1_fix)
Configure the system to not use bridging. # rmmod bridge Edit /etc/modprobe.conf and add a line such as "install bridge /bin/false" to prevent the loading of the bridge module.