3.2.6 Ensure bogus ICMP responses are ignored (Scored) [SecScan]

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======3.2.6 Ensure bogus ICMP responses are ignored (Scored)======
=====Profile Applicability=====  
<code>
Level 1 - Server
Level 1 - Workstation 
</code>

=====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 command and verify output matches:
<Code:bash>
# sysctl net.ipv4.icmp_ignore_bogus_error_responses 
net.ipv4.icmp_ignore_bogus_error_responses = 1
</Code>

=====Remediation===== 
Set the following parameter in the ''/etc/sysctl.conf'' file:
<Code:bash>
net.ipv4.icmp_ignore_bogus_error_responses = 1
</Code>
Run the following commands to set the active kernel parameters:
<Code:bash>
# sysctl -w net.ipv4.icmp_ignore_bogus_error_responses=1 
# sysctl -w net.ipv4.route.flush=1
</Code>