How to catch shells and exploits on php sites?

Question

PHP

Hello everyone,
Is there any tool to catch shells and exploits?
Something to find the connection between $_POST['id'] and index.php modification?

Answer 1

Searching for eval, baase64 might help.
The ideal option is to compare a known clean copy of a site with an infected one.

Answer 2

It's better to just re-upload the files.

Answer 3

There are no means of 100% catching. But there are verification requests by signature. But with a large number of requests, they can load the server quite well.
It is better to do a check with some kind of aibolite or clamming on the crown and see the result.