RHEL 9 must log IPv4 packets with impossible addresses by default.
An XCCDF Rule
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.
- ID
- SV-257961r991589_rule
- Version
- RHEL-09-253030
- Severity
- Medium
- References
- Updated
Remediation Templates
A Manual Procedure
Configure RHEL 9 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