The system must not forward IPv6 source-routed packets.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-72319	RHEL-07-040830	SV-86943r1_rule		Medium

Description
Source-routed packets allow the source of the packet to suggest that routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routed traffic, such as when IPv6 forwarding is enabled and the system is functioning as a router.

STIG	Date
Red Hat Enterprise Linux 7 Security Technical Implementation Guide	2017-07-08

Details

Check Text ( C-72553r1_chk )
Verify the system does not accept IPv6 source-routed packets. Note: If IPv6 is not enabled, the key will not exist, and this is not a finding. Check the value of the accept source route variable with the following command: # /sbin/sysctl -a \| grep net.ipv6.conf.all.accept_source_route net.ipv6.conf.all.accept_source_route=0 If the returned lines do not have a value of "0", or a line is not returned, this is a finding.

Check Text ( C-72553r1_chk )

Verify the system does not accept IPv6 source-routed packets.

Note: If IPv6 is not enabled, the key will not exist, and this is not a finding.

Check the value of the accept source route variable with the following command:

# /sbin/sysctl -a | grep net.ipv6.conf.all.accept_source_route
net.ipv6.conf.all.accept_source_route=0

If the returned lines do not have a value of "0", or a line is not returned, this is a finding.

Fix Text (F-78673r1_fix)
Set the system to the required kernel parameter, if IPv6 is enabled, by adding the following line to "/etc/sysctl.conf" (or modify the line to have the required value): net.ipv6.conf.all.accept_source_route = 0