18.4.2 (L1) Ensure 'MSS: (DisableIPSourceRouting IPv6) IP source routing protection level (protects against packet spoofing)' is set to 'Enabled: Highest protection, source routing is completely disabled'

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Information

IP source routing is a mechanism that allows the sender to determine the IP route that a datagram should follow through the network.
The recommended state for this setting is: Enabled: Highest protection, source routing is completely disabled.

Rationale:
An attacker could use source routed packets to obscure their identity and location. Source routing allows a computer that sends a packet to specify the route that the packet takes.

Solution

To establish the recommended configuration via GP, set the following UI path to Enabled: Highest protection, source routing is completely disabled:
Computer Configuration\Policies\Administrative Templates\MSS (Legacy)\MSS: (DisableIPSourceRouting IPv6) IP source routing protection level (protects against packet spoofing)
Note: This Group Policy path does not exist by default. An additional Group Policy template (MSS-legacy.admx/adml) is required - it is available from this TechNet blog post: The MSS settings ? Microsoft Security Guidance blog

Impact:
All incoming source routed packets will be dropped.

Default Value:
No additional protection, source routed packets are allowed.

References:
1. CCE-33790-7

See Also

https://workbench.cisecurity.org/files/2754