Information
The registry value entry PerformRouterDiscovery was added to the template file in the HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Tcpip\Parameters\ registry key. The entry appears as MSS: (PerformRouterDiscovery) Allow IRDP to detect and configure Default Gateway addresses (could lead to DoS) in the SCE. This setting is used to enable or disable the Internet Router Discovery Protocol (IRDP), which allows the system to detect and configure default gateway addresses automatically as described in RFC 1256 on a per-interface basis. An attacker who has gained control of a computer on the same network segment could configure a computer on the network to impersonate a router. Other computers with IRDP enabled would then attempt to route their traffic through the already compromised computer.
Solution
To implement the recommended configuration state, set the following Group Policy setting to 0.
Computer Configuration\Windows Settings\Security Settings\Local Policies\Security Options\MSS- (PerformRouterDiscovery) Allow IRDP to detect and configure Default Gateway addresses (could lead to DoS)
Impact- If you disable this entry, Windows cannot automatically detect and configure default gateway addresses on the computer.