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Reflected Cross-Site Scripting in QRadar Forensics link analysis page
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Yorick Koster, September 2019

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Abstract
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The QRadar Forensics PHP web application contains a page that is
vulnerable to reflected Cross-Site Scripting. This issue exist due to
the lack of encoding of the single-quote character and can be trigger
without authentication.

This vulnerability allows an attacker to perform a wide variety of
actions such as performing arbitrary actions on the victim's behalf or
presenting a fake login screen to collect usernames and passwords. In
order to exploit this issue, the attacker has to lure a victim into
opening a specially crafted link and pressing a key combination - making
a successful attack less likely. 

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Tested versions
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This issue was successfully verified on QRadar Community Edition [2]
version 7.3.1.6 (7.3.1 Build 20180723171558).

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Fix
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IBM reports that QRadar 7.3.2 Patch 6 is not affected by this
vulnerability. In addtion, it is stated that thist issue is resolved in
QRadar Community Edition version 7.3.3 [3].

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Introduction
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QRadar [4] is IBM's enterprise SIEM [5] solution. A free version of
QRadar is available that is known as QRadar Community Edition [2]. This
version is limited to 50 events per second and 5,000 network flows a
minute, supports apps, but is based on a smaller footprint for
non-enterprise use.

The QRadar Forensics PHP web application contains a page that is
vulnerable to reflected Cross-Site Scripting. This issue exist due to
the lack of encoding of the single-quote character and can be trigger
without authentication.

This vulnerability allows an attacker to perform a wide variety of
actions such as performing arbitrary actions on the victim's behalf or
presenting a fake login screen to collect usernames and passwords. In
order to exploit this issue, the attacker has to lure a victim into
opening a specially crafted link and pressing a key combination - making
a successful attack less likely. 

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Details
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The vulnerability exists in the LinkAnalysis.php page, located in
/opt/ibm/forensics/html/DejaVu/. The page accepts three request
parameters that are reflected in hidden input fields. Their values are
then used to open a new window to load the LinkAnalysisServlet Servlet.
The page itself appears to be old unused code, however it is still
exposed.

/opt/ibm/forensics/html/DejaVu/LinkAnalysis.php:
<?php
  
$solrQuery = htmlentities($_REQUEST['solrQuery']); // e.g., ID:*
$solrDocs = htmlentities($_REQUEST['solrDocs']); // e.g.,
case1-aljazeera_net2.pcap-0800278d2a7a-20080501224316017-1-2, et al.
$solrRows = htmlentities($_REQUEST['solrRows']); // e.g., 1024
  
$SERVER_NAME = $_SERVER['SERVER_NAME'];
  
$servletURL = 'http://' . $SERVER_NAME . ':8080/LinkAnalysisServlet';
$solrURL = 'http://' . $SERVER_NAME . ':8080/solr/documents';
  
print "
[...]
  <input id='solrQuery' value='$solrQuery' hidden></input>
  <input id='solrDocs' value='$solrDocs' hidden></input>
  <input id='solrRows' value='$solrRows' hidden></input>
  <script>
    var solrQuery = document.getElementById('solrQuery').value;
    var solrDocs = document.getElementById('solrDocs').value;
    var solrRows = document.getElementById('solrRows').value;
    
    window.onload = function() {
      window.open('$servletURL?solrURL=$solrURL&solrQuery='+solrQuery+'&solrDocs='+solrDocs+'&solrRows='+solrRows', '_self')
    }
   </script>
[...]

The code above uses the htmlentities() [6] function to escape HTML
characters. The flag argument is not provided, meaning that
htmlentities() will not encode the single-quote character.

The values of the request parameters are reflected between single-quotes
and consequently it is possible to break out of the value attribute and
inject additional attributes in the hidden input field. It isn't
possible to inject other HTML tags as the greater-than and less-than
characters are encoded by htmlentities().

Exploiting Cross-Site Scripting vulnerabilities within hidden fields can
be a bit tricky. A method has been described by Gareth Heyes [7] in the
article XSS in hidden input fields [8]. Essentially it requires that the
victim is enticed to press a certain key combination. This behavior is
also browser [9] and OS dependent. As the attacker also needs to lure a
victim into opening a specially crafted link, exploiting this issue may
proof to be difficult.

This issue can be demonstrated using the proof of concept below. When
loading this URL in Firefox, the victim needs to press Alt+Shift+X
(Windows/Linux) or Ctrl+Alt+X (macOS).

https://<ip>/forensics/DejaVu/LinkAnalysis.php?solrQuery=%27%20accesskey=X%20onclick=%27alert(document.cookie)

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References
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[1] https://www.securify.nl/advisory/SFY20200404/reflected-cross-site-scripting-in-qradar-forensics-link-analysis-page.html
[2] https://developer.ibm.com/qradar/ce/
[3] https://www.ibm.com/account/reg/us-en/signup?formid=urx-32552
[4] https://www.ibm.com/security/security-intelligence/qradar
[5] https://en.wikipedia.org/wiki/Security_information_and_event_management
[6] https://www.php.net/manual/en/function.htmlentities.php
[7] https://twitter.com/garethheyes
[8] https://portswigger.net/blog/xss-in-hidden-input-fields
[9] https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes/accesskey#Browser_compatibility