GEN003604 - The system must not respond to Internet Control Message Protocol (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

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_Oracle_Linux_5_V2R1_STIG.zip

Item Details

Category: ACCESS CONTROL, CONFIGURATION MANAGEMENT

References: 800-53|AC-4, 800-53|CM-6d., 800-53|CM-7b., CAT|II, CCI|CCI-000382, CCI|CCI-001503, CCI|CCI-001551, Rule-ID|SV-218483r603259_rule, STIG-ID|GEN003604, STIG-Legacy|SV-64195, STIG-Legacy|V-22411, Vuln-ID|V-218483

Plugin: Unix

Control ID: 18ea76920d29391210ec8e475c05314e0fbf0b410bbc46786ee5a5641fd39c11