TOSS 5 must log IPv4 packets with impossible addresses by default.

Overview

Finding IDVersionRule IDIA ControlsSeverity
V-282688TOSS-05-000216SV-282688r1201044_ruleCCI-000366medium
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.
STIGDate
Tri-Lab Operating System Stack (TOSS) 5 Security Technical Implementation Guide2026-04-01

Details

Check Text (C-282688r1201044_chk)

Verify TOSS 5 logs IPv4 martian packets by default using the following command: $ sudo sysctl net.ipv4.conf.default.log_martians net.ipv4.conf.default.log_martians = 1 If "net.ipv4.conf.default.log_martians" is not set to "1" , or a line is not returned, this is a finding.

Fix Text (F-87154r1201043_fix)

Configure TOSS 5 to log martian packets on IPv4 interfaces by default. Add or edit the following line in a single system configuration file, in the "/etc/sysctl.d/" directory: net.ipv4.conf.default.log_martians=1 Load settings from all system configuration files using the following command: $ sudo sysctl --system