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

From SLES 12 Security Technical Implementation Guide

Associated with: CCI-000366

SV-92187r1_rule The SUSE operating system must not respond to Internet Protocol version 4 (IPv4) Internet Control Message Protocol (ICMP) echoes sent to a broadcast address.

Vulnerability discussion

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

Check content

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

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

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