RHEL-09-253030 - RHEL 9 must log IPv4 packets with impossible addresses by default.

Information

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.

Solution

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

Load settings from all system configuration files with the following command:

$ sudo sysctl --system

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_RHEL_9_V2R3_STIG.zip

Item Details

Category: CONFIGURATION MANAGEMENT

References: 800-53|CM-6b., CAT|II, CCI|CCI-000366, Rule-ID|SV-257961r991589_rule, STIG-ID|RHEL-09-253030, Vuln-ID|V-257961

Plugin: Unix

Control ID: 897a7196ee414f497caa127ebe28bcbcaef023fd9b3890a29691d01b73810619