Finding ID | Version | Rule ID | IA Controls | Severity |
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V-22411 | GEN003604 | SV-45723r1_rule | Medium |
Description |
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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. |
STIG | Date |
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SUSE Linux Enterprise Server v11 for System z | 2016-12-20 |
Check Text ( C-43090r1_chk ) |
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Verify the system does not respond to ICMP TIMESTAMP_REQUESTs set to broadcast addresses. Procedure: # cat /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts If the result is not 1, this is a finding. Note: The same parameter controls both ICMP ECHO_REQUESTs and TIMESTAMP_REQUESTs. |
Fix Text (F-39121r1_fix) |
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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 |