The system must log Martian packets.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-217917	RHEL-06-000088	SV-217917r505923_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	2020-09-03

Details

Check Text ( C-19398r376766_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 net.ipv4.conf.all.log_martians = 1 $ grep net.ipv4.conf.all.log_martians /etc/sysctl.conf /etc/sysctl.d/* net.ipv4.conf.all.log_martians = 1 If "net.ipv4.conf.all.log_martians" is not configured in the /etc/sysctl.conf file or in the /etc/sysctl.d/ directory, is commented out or does not have a value of "1", this is a finding.

Fix Text (F-19396r376767_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 Set the system to the required kernel parameter by adding the following line to "/etc/sysctl.conf" or a config file in the /etc/sysctl.d/ directory (or modify the line to have the required value): net.ipv4.conf.all.log_martians = 1 Issue the following command to make the changes take effect: # sysctl --system