The system must ignore IPv4 Internet Control Message Protocol (ICMP) redirect messages.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-22416	GEN003609	SV-37626r1_rule	ECSC-1	Medium

Description
ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack.

STIG	Date
Red Hat Enterprise Linux 5 Security Technical Implementation Guide	2014-07-02

Details

Check Text ( None )
None

Fix Text (F-31663r1_fix)
Configure the system to not accept IPv4 ICMP redirect messages. Edit /etc/sysctl.conf and add a setting for "net.ipv4.conf.all.accept_redirects=0" and "net.ipv4.conf.default.accept_redirects=0". # sysctl -p