RHEL-09-254040 - RHEL 9 must not forward IPv6 source-routed packets by default.

Information

Source-routed packets allow the source of the packet to suggest that routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routed traffic, such as when forwarding is enabled and the system is functioning as a router.

Accepting source-routed packets in the IPv6 protocol has few legitimate uses. It must be disabled unless it is absolutely required.

Solution

Configure RHEL 9 to not forward IPv6 source-routed packets by default.

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

net.ipv6.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_V2R4_STIG.zip

Item Details

Category: CONFIGURATION MANAGEMENT

References: 800-53|CM-6b., CAT|II, CCI|CCI-000366, Rule-ID|SV-257977r991589_rule, STIG-ID|RHEL-09-254040, Vuln-ID|V-257977

Plugin: Unix

Control ID: ac868c909a75ce2ce6e6a27c3086d57d9f3b99e7d1fb13872fb2c9aff752e342