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

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

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.icmp_echo_ignore_broadcasts net.ipv4.icmp_echo_ignore_broadcasts = 1

If the returned line does not have a value of "1" this is a finding.

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.icmp_echo_ignore_broadcasts = 1

Run the following command to apply this value:

# sysctl --system