The OS X system must not process Internet Control Message Protocol [ICMP] timestamp requests.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-76147	AOSX-12-001220	SV-90835r1_rule		Medium

Description
ICMP timestamp requests reveal information about the system and can be used to determine which operating system is installed. Precise time data can also be used to launch time-based attacks against the system. Configuring the system to drop incoming ICMPv4 timestamp requests mitigates these risks.

STIG	Date
Apple OS X 10.12 Security Technical Implementation Guide	2018-12-24

Details

Check Text ( C-75833r1_chk )
To check if the system is configured to process ICMP timestamp requests, run the following command: sysctl net.inet.icmp.timestamp If the value is not set to "0", this is a finding.

Fix Text (F-82785r1_fix)
To disable ICMP timestamp responses, add the following line to "/etc/sysctl.conf", creating the file if necessary: net.inet.icmp.timestamp=0