The SUSE operating system must not respond to Internet Protocol version 4 (IPv4) Internet Control Message Protocol (ICMP) echoes sent to a broadcast address.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-77491	SLES-12-030380	SV-92187r1_rule		Medium

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

STIG	Date
SLES 12 Security Technical Implementation Guide	2018-09-27

Details

Check Text ( C-77051r1_chk )
Verify the SUSE operating system does not accept IPv4 source-routed packets. Check the value of the accept source route variable with the following command: # sysctl net.ipv4.conf.all.accept_source_route net.ipv4.conf.all.accept_source_route = 0 If the returned line does not have a value of "0" this is a finding.

Fix Text (F-84133r1_fix)
Configure the SUSE operating system to the required kernel parameter by adding the following line to "/etc/sysctl.conf" (or modify the line to have the required value): net.ipv4.conf.all.accept_source_route = 0 Run the following command to apply this value: # sysctl --system