Is that some kind of PHP backdoor

I found this code in my website files is that some kind of backdoor ?
can someone explain this code line by line

<? $_="{";

yes it is. It gets two values from $_GET with the keys _ and __ and then makes a function call to _ passing in __.

You can do lots of bad stuff when you can execute whatever function you want with whatever input you want.

Sponsor our Newsletter | Privacy Policy | Terms of Service