RHEL-09-253045 - RHEL 9 must not forward IPv4 source-routed packets by default.

Information

Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures.

Accepting source-routed packets in the IPv4 protocol has few legitimate uses. It must be disabled unless it is absolutely required, such as when IPv4 forwarding is enabled and the system is legitimately functioning as a router.

Solution

Configure RHEL 9 to not forward IPv4 source-routed packets by default.

Add or edit the following line in a single system configuration file, in the "/etc/sysctl.d/" directory:

net.ipv4.conf.default.accept_source_route = 0

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-257964r991589_rule, STIG-ID|RHEL-09-253045, Vuln-ID|V-257964

Plugin: Unix

Control ID: 5827e2f5c53daed89f213c7a8daf23321f1ff27328066ef68724e5ab8339c136