| # 3.2.6 Ensure bogus ICMP responses are ignored |
| # |
| # Description |
| # =========== |
| # 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. |
| # |
| # Audit |
| # ===== |
| # |
| # Run the following commands and verify output matches: |
| # |
| # # sysctl net.ipv4.icmp_ignore_bogus_error_responses |
| # net.ipv4.icmp_ignore_bogus_error_responses = 1 |
| # |
| # Remediation |
| # =========== |
| # |
| # Set the following parameter in the /etc/sysctl.conf file: |
| # |
| # net.ipv4.icmp_ignore_bogus_error_responses = 1 |
| # |
| # Run the following commands to set the active kernel parameters: |
| # |
| # # sysctl -w net.ipv4.icmp_ignore_bogus_error_responses=1 |
| # # sysctl -w net.ipv4.route.flush=1 |
| |
| parameters: |
| linux: |
| system: |
| kernel: |
| sysctl: |
| net.ipv4.icmp_ignore_bogus_error_responses: 1 |