18.5.2 Ensure 'MSS: (DisableIPSourceRouting IPv6) IP source routing protection level' is set to 'Enabled: Highest protection, source routing is completely disabled'

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.

A threat actor 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

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 https://blogs.technet.microsoft.com/secguide/2016/10/02/the-mss-settings/

Impact:

All incoming source routed packets will be dropped.

See Also

https://workbench.cisecurity.org/benchmarks/25708

Item Details

Category: CONFIGURATION MANAGEMENT

References: 800-53|CM-6, CSCv7|5.1

Plugin: Windows

Control ID: 41b18e050408b9c2259f033bc119773465bb3ff1003fd03fae8057d9c6e490d2