Using a shared cache in a Web farm environment for detecting replay attacks in WCF

Question

Hello,

I'm trying to figure out how to implement a replay attack detection mechanism with WCF in a web farm scenario.

WCF provides such detection mechanism by using a nonce cache. Correct me if I'm wrong, but the only way to ensure to prevent this attack in a message security and web farm scenario is by using a nonce cache shared across the servers.

In WSE3.0, it used to be possible to provide nonce cache custom implementations

http://msdn.microsoft.com/en-us/library/ff647945.aspx

but there doesn't seem to be any way to do so in WCF (No configuration options, besides I found with Reflector that the NonceCache class is marked as both sealed and internal..)

Any thoughts?