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

From MAC OSX 10.6 Workstation Security Technical Implementation Guide

Associated with IA controls: ECSC-1

Associated with: CCI-001551

SV-38201r1_rule The system must not respond to Internet Control Message Protocol (ICMPv4) 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

Open a terminal session and enter the following command to view the value of "net.inet.icmp.bmcastecho". sysctl -a | grep net.inet.icmp.bmcastecho If the value is not set to "1", this is a finding.

Fix text

Open a terminal session and edit the /etc/sysctl.conf file and add the following line. net.inet.icmp.bmcastecho=1 NOTE: If the sysctl.conf file does not exist use the following command to create one. touch /etc/sysctl.conf

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