3.2.6 Ensure bogus ICMP responses are ignored - sysctl.conf/sysctl.d

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

Set the following parameter in /etc/sysctl.conf or a /etc/sysctl.d/* 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

/etc is stateless on Container-Optimized OS. Therefore, /etc cannot be used to make these changes persistent across reboots. The steps mentioned above needs to be performed after every boot.

See Also

https://workbench.cisecurity.org/files/3659

Item Details

Category: CONFIGURATION MANAGEMENT, CONTINGENCY PLANNING, PLANNING, PROGRAM MANAGEMENT, SYSTEM AND SERVICES ACQUISITION, SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|CM-7, 800-53|CP-6, 800-53|CP-7, 800-53|PL-8, 800-53|PM-7, 800-53|SA-8, 800-53|SC-7, CSCv7|5.1

Plugin: Unix

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