Is there a way to block CURL to fetch data on my site?

php curl

Yes, I am sure curl has a default User-Agent, but that is obviously something that can be changed as easily as -H 'User-Agent=Poop'

In fact, I think there is a switch specifically for setting the user agent. -A

php curl

curl user agents can be changed at any time. The reason curl exists is that you can change pretty much everything on your query.

You can block them, but once they change the use agent, they will have access again.

I recommend you block the IP address instead or the whole subnet just to be sure.

Example:

deny from aa.bb.cc.dd  ff.gg.hh.0/24

php curl

You can check preferred language, http version, remote domain and such things.

CodeHunter