The system must log Martian packets.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-38528	RHEL-06-000088	SV-50329r1_rule		Low

Description
The presence of "martian" packets (which have impossible addresses) as well as spoofed packets, source-routed packets, and redirects could be a sign of nefarious network activity. Logging these packets enables this activity to be detected.

STIG	Date
Red Hat Enterprise Linux 6 Security Technical Implementation Guide	2014-06-11

Details

Check Text ( C-46086r2_chk )
The status of the "net.ipv4.conf.all.log_martians" kernel parameter can be queried by running the following command: $ sysctl net.ipv4.conf.all.log_martians The output of the command should indicate a value of "1". If this value is not the default value, investigate how it could have been adjusted at runtime, and verify it is not set improperly in "/etc/sysctl.conf". If the correct value is not returned, this is a finding.

Check Text ( C-46086r2_chk )

The status of the "net.ipv4.conf.all.log_martians" kernel parameter can be queried by running the following command:

$ sysctl net.ipv4.conf.all.log_martians

The output of the command should indicate a value of "1". If this value is not the default value, investigate how it could have been adjusted at runtime, and verify it is not set improperly in "/etc/sysctl.conf".
If the correct value is not returned, this is a finding.

Fix Text (F-43476r1_fix)
To set the runtime status of the "net.ipv4.conf.all.log_martians" kernel parameter, run the following command: # sysctl -w net.ipv4.conf.all.log_martians=1 If this is not the system's default value, add the following line to "/etc/sysctl.conf": net.ipv4.conf.all.log_martians = 1