The system must not respond to Internet Control Message Protocol v4 (ICMPv4) echoes sent to a broadcast address.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-22410	GEN003603	SV-37608r1_rule	ECSC-1	Medium

Description
Responding to broadcast (ICMP) echoes facilitates network mapping and provides a vector for amplification attacks.

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

Details

Check Text ( None )
None

Fix Text (F-31641r1_fix)
Configure the system to not respond to ICMP ECHO_REQUESTs sent to broadcast addresses. Edit /etc/sysctl.conf and add a setting for "net.ipv4.icmp_echo_ignore_broadcasts=1" and reload the sysctls. Procedure: # echo "net.ipv4.icmp_echo_ignore_broadcasts=1" >> /etc/sysctl.conf # sysctl -p