3.2.6 Ensure bogus ICMP responses are ignored

Information

Setting icmp_ignore_bogus_error_responses to 1 prevents the kernel from logging bogus responses (RFC-1122 non-compliant) from broadcast reframes, keeping file systems from filling up with useless log messages.

Rationale:

Some routers (and some attackers) will send responses that violate RFC-1122 and attempt to fill up a log file system with many useless error messages.

Solution

Run the following command to set the active kernel parameter and persist the setting:

# apiclient apply <<EOF
[settings.kernel.sysctl]
"net.ipv4.icmp_ignore_bogus_error_responses" = "1"
EOF

Run the following command to flush the routing cache:

# sysctl -w net.ipv4.route.flush=1

See Also

https://workbench.cisecurity.org/benchmarks/6709

Item Details

Category: CONFIGURATION MANAGEMENT, SYSTEM AND SERVICES ACQUISITION

References: 800-53|CM-1, 800-53|CM-2, 800-53|CM-6, 800-53|CM-7, 800-53|CM-7(1), 800-53|CM-9, 800-53|SA-3, 800-53|SA-8, 800-53|SA-10, CSCv7|5.1

Plugin: Unix

Control ID: 9df3e58a5d40793c94c995260ebbe047091199fb0dd8ea176dc6734d33fa7db0