GEN003604 - The system must not respond to ICMP timestamp requests sent to a broadcast address.

Information

The processing of (ICMP) timestamp requests increases the attack surface of the system. Responding to broadcast ICMP timestamp requests facilitates network mapping and provides a vector for amplification attacks.

Solution

Configure the system to not respond to ICMP TIMESTAMP_REQUESTs sent to broadcast addresses. Edit /etc/sysctl.conf and add a setting for 'net.ipv4.icmp_echo_ignore_broadcasts=1' and reload the sysctls.

Procedure:
# echo 'net.ipv4.icmp_echo_ignore_broadcasts=1' >> /etc/sysctl.conf
# sysctl -p

See Also

http://iasecontent.disa.mil/stigs/zip/U_RedHat_5_V1R17_STIG.zip

Item Details

Category: SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|SC-7, CAT|II, CCI|CCI-001551, Group-ID|V-22411, Rule-ID|SV-29288r1_rule, STIG-ID|GEN003604

Plugin: Unix

Control ID: aa053183bde8acbb199e706a985e35f98cca4af10e1e427feeb70e462f765ad8