OL 9 must log IPv4 packets with impossible addresses.
Severity | Group ID | Group Title | Version | Rule ID | Date | STIG Version |
|---|---|---|---|---|---|---|
| medium | V-271866 | SRG-OS-000480-GPOS-00227 | OL09-00-006022 | SV-271866r1092310_rule | 2025-05-08 | 1 |
| 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. |
| ℹ️ Check |
|---|
| Verify that OL 9 logs IPv4 martian packets. Check the value of the accept source route variable with the following command: $ sysctl net.ipv4.conf.all.log_martians net.ipv4.conf.all.log_martians = 1 If the returned line does not have a value of "1", a line is not returned, or the line is commented out, this is a finding. |
| ✔️ Fix |
|---|
| Configure OL 9 to log martian packets on IPv4 interfaces. Add or edit the following line in a single system configuration file in the "/etc/sysctl.d/" directory: net.ipv4.conf.all.log_martians=1 Load settings from all system configuration files with the following command: $ sudo sysctl --system |