3.3.6 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.

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:

Example:

# printf "
net.ipv4.icmp_ignore_bogus_error_responses = 1
" >> /etc/sysctl.d/60-netipv4_sysctl.conf

Run the following command to set the active kernel parameters:

# {
sysctl -w net.ipv4.icmp_ignore_bogus_error_responses=1
sysctl -w net.ipv4.route.flush=1
}

See Also

https://workbench.cisecurity.org/files/3742

Item Details

Category: CONFIGURATION MANAGEMENT, SYSTEM AND SERVICES ACQUISITION

References: 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: 39d044cdcd96823d44a8ca35e426ff23cf147da836674d7755933dbdf7622ab7