How to block (Empty X-Requested-With header)

I’ve seen this asked before but can’t find an answer: how can I block (Empty X-Requested-With header)? I’m sure there’s a way to do it with a rule or something, I just don’t know how.

Hi there,

Please check this documentation on creating Firewall rules:

Thank you.

any(http.request.headers["x-requested-with"][*] contains "") 
and (http.request.full_uri contains "host.example.com/some/uri/path")