[waraxe-2005-SA#039] - Critical Sql Injection in Sgallery module for PhpNuke

[Janek Vind <come2waraxe@xxxxxxxxx>]

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{                              [waraxe-2005-SA#039]                             
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{             [ Critical Sql Injection in Sgallery module for PhpNuke ]         
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Author: Janek Vind "waraxe"
Date: 12. January 2005
Location: Estonia, Tartu
Web: http://www.waraxe.us/advisory-39.html


Affected software description:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Module's Name: SGallery
Module's Version: 1.01
Module's Description: Simple JPG image gallery
License: GNU/GPL
Author's Name: Sergey Kiselev
Author's Email: ser@xxxxxxxxxxxxxx

Homepage: http://www.ser.acmetelecom.ru


Vulnerabilities:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Let's look at source code from imageview.php:


----------------[ original code ]---------------

require_once("$DOCUMENT_ROOT/config.php");
require_once("$DOCUMENT_ROOT/includes/sql_layer.php");
  
  $dbi = sql_connect ($dbhost,$dbuname,$dbpass,$dbname);

  if ($idalbum) {
    $result = sql_query("select picture from ".$prefix."_SGalbums where 
idalbum=".$idalbum,$dbi);
  } elseif ($idimage) {
    $result = sql_query("select picture from ".$prefix."_SGimages where 
idimage=".$idimage,$dbi);
  }

  list($echo) = sql_fetch_row($result, $dbi);
  sql_free_result($result);

  sql_logout ($dbi);

  header ("Content-Type: image/jpeg");
  echo $echo;

----------------[ /original code ]---------------

Now let's analyze the weak points.


A - Full Path Disclosure
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

If "$idalbum" and "$idimage" are both unset, then because of the open 
"if/elseif" construction
there variable "$result" will be unset or can be poisoned through 
GET/POST/COOKIE.
And next call of the "sql_fetch_row()" will trigger generic php error messages, 
leading to
full path disclosure. Path disclosure is considered as low level security 
threat, but anyway it's
useful for further malicious actions.


B - Potential arbitrary file inclusion:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

This kind of code construction as

require_once("$DOCUMENT_ROOT/config.php");
require_once("$DOCUMENT_ROOT/includes/sql_layer.php");

is not very secure. Depending of the webserver software vendor,version number 
and configuration
settings it can lead to arbitrary file inclusion and possible remote file 
inclusion.


C - Critical sql injection bug in "imageview.php":
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Looking at source code, presented above, we can see unsecure sql queries 
directed to the database.
To be excact, user submitted variables "$idalbum" and/or "$idimage" are used in 
sql "SELECT" clause
without escaping with single quotes. This is clearly sql injection bug. Further 
exploitation will
depend on database software and version. In case of the mysql version 4.x with 
UNION functionality enabled,
arbitrary data can be retrieved from database, inluding admin(s) authentication 
credentials.
Traditionally, there is the proof of concept:


----------------[ real life exploit ]---------------

http://localhost/nuke75/modules/Sgallery/imageview.php?idimage=-99/**/UNION/
**/SELECT/**/pwd/**/FROM/**/nuke_authors/**/WHERE/**/radminsuper=1

----------------[/real life exploit ]---------------

Best browser to test this POC is MSIE - it will show plaintext admin password's 
md5 hash as needed.
Firefox and other browsers will mostly rendering out "broken picture" because 
of the
"Content-Type: image/jpeg" header. But anyway, sql injection exists, can be 
exploited and must be
fixed by vendor as soon as possible.


How to fix:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Developer first contacted: 16. November 2004
No response from developer after multiple sent emails.
Downloadable version of the Sgalley is still unpatched.

How to fix this security hole - http://www.waraxe.us/forums.html


Additional resources:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Base64 encoder and decoder - http://base64-encoder-online.waraxe.us/
SiteMapper - free php script for phpNuke powered websites - 
http://sitemapper.waraxe.us/
It's easy to install solution for making phpNuke more Google friendly!


Greetings:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Greets to icenix, Raido Kerna, g0df4th3r and slimjim100!
Tervitused - Heintz!

Contact:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    come2waraxe@xxxxxxxxx
    Janek Vind "waraxe"

    Homepage: http://www.waraxe.us/

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