The system must ignore ICMPv4 redirect messages by default.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-38533	RHEL-06-000091	SV-50334r3_rule		Low

Description
This feature of 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	2015-05-26

Details

Check Text ( C-46091r2_chk )

The status of the "net.ipv4.conf.default.accept_redirects" kernel parameter can be queried by running the following command: $ sysctl net.ipv4.conf.default.accept_redirects The output of the command should indicate a value of "0". If this value is not the default value, investigate how it could have been adjusted at runtime, and verify it is not set improperly in "/etc/sysctl.conf". $ grep net.ipv4.conf.default.accept_redirects /etc/sysctl.conf If the correct value is not returned, this is a finding.

Fix Text (F-43481r1_fix)
To set the runtime status of the "net.ipv4.conf.default.accept_redirects" kernel parameter, run the following command: # sysctl -w net.ipv4.conf.default.accept_redirects=0 If this is not the system's default value, add the following line to "/etc/sysctl.conf": net.ipv4.conf.default.accept_redirects = 0