The system must not process Internet Control Message Protocol (ICMP) timestamp requests.

From Oracle Linux 5 Security Technical Implementation Guide

Associated with: CCI-001551

SV-64445r2_rule The system must not process Internet Control Message Protocol (ICMP) timestamp requests.

Vulnerability discussion

The processing of (ICMP) timestamp requests increases the attack surface of the system.

Check content

Verify the system does not respond to ICMP TIMESTAMP-REQUESTs Procedure: # grep "timestamp" /etc/sysconfig/iptables This should return entries for "timestamp-reply" and "timestamp-request". Both should end with "-j DROP'. If either does not exist or does not "DROP" the message, this is a finding.

Fix text

Configure the system to not respond to ICMP TIMESTAMP-REQUESTs. This is done by rejecting ICMP type 13 and 14 messages at the firewall. Procedure: Edit /etc/sysconfig/iptables to add: -A RH-Firewall-1-INPUT -p ICMP --icmp-type timestamp-request -j DROP -A RH-Firewall-1-INPUT -p ICMP --icmp-type timestamp-reply -j DROP Restart the firewall: # service iptables restart

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