UCF STIG Viewer Logo
Changes are coming to https://stigviewer.com. Take our survey to help us understand your usage and how we can better serve you in the future.
Take Survey

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


Overview

Finding ID Version Rule ID IA Controls Severity
V-22409 GEN003602 SV-45721r1_rule ECSC-1 Low
Description
The processing of (ICMP) timestamp requests increases the attack surface of the system.
STIG Date
SUSE Linux Enterprise Server v11 for System z 2015-10-20

Details

Check Text ( C-43088r1_chk )
Verify the system does not respond to ICMP TIMESTAMP_REQUESTs

Procedure:

# iptables -L INPUT | grep "timestamp"


This should return the following entries for "timestamp-reply" and "timestamp_request":
DROP icmp -- anywhere anywhere icmp timestamp-request
DROP icmp -- anywhere anywhere icmp timestamp-reply

If either does not exist or does not "DROP" the message, this is a finding.
Fix Text (F-39119r1_fix)
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:

1. Check the SuSEfirewall2 configuration to see if custom rules are being used:

# grep -v '^#' /etc/sysconfig/SuSEfirewall2 | grep FW_CUSTOMRULES

If the command returns FW_CUSTOMRULES=”” then no custom rules are being used. In that case edit the /etc/sysconfig/SuSEfirewall2 file and use the vendor supplied file by setting FW_CUSTOMRULES="/etc/sysconfig/scripts/SuSEfirewall2-custom"

2. Edit the file defined by the FW_CUSTOMRULES variable and add these commands to append the INPUT chain:

iptables -A INPUT -p ICMP --icmp-type timestamp-request -j DROP
iptables -A INPUT -p ICMP --icmp-type timestamp-reply -j DROP

Restart the firewall:

# rcSuSEfirewall2 restart