Strange in the logs on the site

Question

Bots

Not so long ago, something strange began to appear in the logs of the site instead of identifying the browser.
Namely:
<?php system("id"); ?>

The geography of IP addresses from where this comes from is quite wide
(so far only 13 pieces in the ban village).

But the question is - what did they try to achieve?
And who else has such lines found in the logs?

Answer 1

I have the same ones. There are only 7 posts so far.
The purpose of their visit seems to be obvious: they scan holes, look for vulnerabilities.
Requests:
/?mod=../../../../../../proc/self/environ
/?page=../../../../../../proc/self/environ
/?file=../../../../../../proc/self/environ

Answer 2

foro.undersecurity.net/read.php?15,3768 In short ,
you are being scanned for local file inclusion