The system must not accept IPv4 source-routed packets by default.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-217918	RHEL-06-000089	SV-217918r505923_rule		Medium

Description
Accepting source-routed packets in the IPv4 protocol has few legitimate uses. It should be disabled unless it is absolutely required.

STIG	Date
Red Hat Enterprise Linux 6 Security Technical Implementation Guide	2020-09-03

Details

Check Text ( C-19399r376769_chk )

The status of the "net.ipv4.conf.default.accept_source_route" kernel parameter can be queried by running the following command: $ sysctl net.ipv4.conf.default.accept_source_route net.ipv4.conf.default.accept_source_route = 0 $ grep net.ipv4.conf.default.accept_source_route /etc/sysctl.conf /etc/sysctl.d/* net.ipv4.conf.default.accept_source_route = 0 If "net.ipv4.conf.default.accept_source_route" is not configured in the /etc/sysctl.conf file or in the /etc/sysctl.d/ directory, is commented out or does not have a value of "0", this is a finding.

Fix Text (F-19397r376770_fix)

To set the runtime status of the "net.ipv4.conf.default.accept_source_route" kernel parameter, run the following command: # sysctl -w net.ipv4.conf.default.accept_source_route=0 Set the system to the required kernel parameter by adding the following line to "/etc/sysctl.conf" or a config file in the /etc/sysctl.d/ directory (or modify the line to have the required value): net.ipv4.conf.default.accept_source_route = 0 Issue the following command to make the changes take effect: # sysctl --system