Block empty query using ASM.

Hello,

 

We've seen numerous requests to our application that contain an empty query string at the root directory i.e. https://www.domain.com/? I'd like to block them.

 

Currently there is an iRule in place to stop this type of request:

 

{ [HTTP::uri] equals "/?"}

 

We'd like to move the blocking of this type of request from an iRule to ASM. So far I have the following signature:

 

uricontent:"/?"; re2:"/\s\/\?\s/";

 

I can't work out a way of saying exact matches using ASM signatures in the same way as is done with the iRule. The only way I could find of completing the task was to look for the whitespace on either side of the /? in the request.

 

Can anyone think of better syntax for the signature, or a built in feature of ASM that I have missed, for completing this task?

 

Thanks.