XSS, Cross Site Scripting, CWE-79, CAPEC-86, parallels.com

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Report generated by XSS.CX at Thu Apr 14 14:18:06 CDT 2011.

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1. Cross-site scripting (reflected)

2. Cross-domain script include

3. Content type incorrectly stated


1. Cross-site scripting (reflected)  next

Summary

Severity:   High
Confidence:   Certain
Host:   http://www.parallels.com
Path:   /geo,il/en/geo/utw7-buy-woc4/

Issue detail

The value of the jscontainer request parameter is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 2c376\"%3balert(1)//55eeb43f561 was submitted in the jscontainer parameter. This input was echoed as 2c376\\";alert(1)//55eeb43f561 in the application's response.

This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.

The application attempts to prevent termination of the quoted JavaScript string by placing a backslash character (\) before any quotation mark characters contained within the input. The purpose of this defence is to escape the quotation mark and prevent it from terminating the string. However, the application fails to escape any backslash characters that already appear within the input itself. This enables an attacker to supply their own backslash character before the quotation mark, which has the effect of escaping the backslash character added by the application, and so the quotation mark remains unescaped and succeeds in terminating the string. This technique is used in the attack demonstrated.

Remediation detail

Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context. If it is unavoidable to echo user input into a quoted JavaScript string the the backslash character should be blocked, or escaped by replacing it with two backslashes.

Issue background

Reflected cross-site scripting vulnerabilities arise when data is copied from a request and echoed into the application's immediate response in an unsafe way. An attacker can use the vulnerability to construct a request which, if issued by another application user, will cause JavaScript code supplied by the attacker to execute within the user's browser in the context of that user's session with the application.

The attacker-supplied code can perform a wide variety of actions, such as stealing the victim's session token or login credentials, performing arbitrary actions on the victim's behalf, and logging their keystrokes.

Users can be induced to issue the attacker's crafted request in various ways. For example, the attacker can send a victim a link containing a malicious URL in an email or instant message. They can submit the link to popular web sites that allow content authoring, for example in blog comments. And they can create an innocuous looking web site which causes anyone viewing it to make arbitrary cross-domain requests to the vulnerable application (using either the GET or the POST method).

The security impact of cross-site scripting vulnerabilities is dependent upon the nature of the vulnerable application, the kinds of data and functionality which it contains, and the other applications which belong to the same domain and organisation. If the application is used only to display non-sensitive public content, with no authentication or access control functionality, then a cross-site scripting flaw may be considered low risk. However, if the same application resides on a domain which can access cookies for other more security-critical applications, then the vulnerability could be used to attack those other applications, and so may be considered high risk. Similarly, if the organisation which owns the application is a likely target for phishing attacks, then the vulnerability could be leveraged to lend credibility to such attacks, by injecting Trojan functionality into the vulnerable application, and exploiting users' trust in the organisation in order to capture credentials for other applications which it owns. In many kinds of application, such as those providing online banking functionality, cross-site scripting should always be considered high risk.

Remediation background

In most situations where user-controllable data is copied into application responses, cross-site scripting attacks can be prevented using two layers of defences:In cases where the application's functionality allows users to author content using a restricted subset of HTML tags and attributes (for example, blog comments which allow limited formatting and linking), it is necessary to parse the supplied HTML to validate that it does not use any dangerous syntax; this is a non-trivial task.

Request

GET /geo,il/en/geo/utw7-buy-woc4/?jscontainer=utw7-buy-woc22c376\"%3balert(1)//55eeb43f561 HTTP/1.1
Host: www.parallels.com
Proxy-Connection: keep-alive
Referer: http://www.parallels.com/
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.16 (KHTML, like Gecko) Chrome/10.0.648.204 Safari/534.16
Accept: */*
Accept-Encoding: gzip,deflate,sdch
Accept-Language: en-US,en;q=0.8
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3
Cookie: region=en|; __utmz=1.1302790956.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none); __utma=1.713730540.1302790956.1302790956.1302790956.1; __utmc=1; __utmb=1.1.10.1302790956

Response

HTTP/1.0 200 OK
Date: Thu, 14 Apr 2011 14:32:19 GMT
Server: Apache/2.2.3 (CentOS)
Set-Cookie: aspcms_sid=56a82ff1eb8463535de2ef8e63493f89; path=/; domain=.parallels.com; expires=Fri, 13-Apr-2012 14:32:19 GMT; HTTPOnly
Expires: Fri, 15 Apr 2011 14:32:19 GMT
Content-Type: text/javascript
X-Cache: MISS from www.parallels.com
X-Cache-Lookup: MISS from www.parallels.com:80
Connection: close

document.getElementById("utw7-buy-woc22c376\\";alert(1)//55eeb43f561").innerHTML = '<a href="http://store.parallels.com/store/para/en_US/buy/productID.197838000" class="rbtn"><span>Buy Now! $39.99</sp
...[SNIP]...
2. Cross-domain script include  previous  next

Summary

Severity:   Information
Confidence:   Certain
Host:   http://www.parallels.com
Path:   /

Issue detail

The response dynamically includes the following scripts from other domains:

Issue background

When an application includes a script from an external domain, this script is executed by the browser within the security context of the invoking application. The script can therefore do anything that the application's own scripts can do, such as accessing application data and performing actions within the context of the current user.

If you include a script from an external domain, then you are trusting that domain with the data and functionality of your application, and you are trusting the domain's own security to prevent an attacker from modifying the script to perform malicious actions within your application.

Issue remediation

Scripts should not be included from untrusted domains. If you have a requirement which a third-party script appears to fulfil, then you should ideally copy the contents of that script onto your own domain and include it from there. If that is not possible (e.g. for licensing reasons) then you should consider reimplementing the script's functionality within your own code.

Request

GET / HTTP/1.1
Host: www.parallels.com
Proxy-Connection: keep-alive
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.16 (KHTML, like Gecko) Chrome/10.0.648.204 Safari/534.16
Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5
Accept-Encoding: gzip,deflate,sdch
Accept-Language: en-US,en;q=0.8
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3

Response

HTTP/1.0 200 OK
Date: Thu, 14 Apr 2011 14:13:28 GMT
Server: Apache/2.2.3 (CentOS)
Last-Modified: 14 Apr 2011 05:00:24 -0400
Expires: Thu, 14 Apr 2011 14:33:28 GMT
Content-Type: text/html; charset=UTF-8
Age: 993
Content-Length: 42634
X-Cache: HIT from www.parallels.com
X-Cache-Lookup: HIT from www.parallels.com:80
Connection: keep-alive

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="X-UA-Comp
...[SNIP]...
</script>
<script type="text/javascript" src="//ajax.googleapis.com/ajax/libs/jquery/1.4/jquery.min.js"></script>
<script type="text/javascript" src="//drh.img.digitalriver.com/DRHM/Storefront/Library/scripts/DigitalRiverOTPageLevelCode.js"></script>
<script type="text/javascript" src="//store.digitalriver.com/DRHM/Storefront/Site/parastor/cm/multimedia/OT_Files/en/parastor_global_trial.js"></script>
<script type="text/javascript" src="//store.digitalriver.com/DRHM/Storefront/Site/parastor/cm/multimedia/OT_Files/en/parastor_HomepageEN_contentBody.js"></script>
...[SNIP]...
</script><script type="text/javascript" src="https://lct.salesforce.com/sfga.js"></script>
...[SNIP]...
</script><script src="http://display.digitalriver.com/?aid=244&tax=par" type="text/javascript" defer="defer"></script>
...[SNIP]...
3. Content type incorrectly stated  previous

Summary

Severity:   Information
Confidence:   Firm
Host:   http://www.parallels.com
Path:   /geo/util/js/country/

Issue detail

The response contains the following Content-type statement:The response states that it contains script. However, it actually appears to contain plain text.

Issue background

If a web response specifies an incorrect content type, then browsers may process the response in unexpected ways. If the specified content type is a renderable text-based format, then the browser will usually attempt to parse and render the response in that format. If the specified type is an image format, then the browser will usually detect the anomaly and will analyse the actual content and attempt to determine its MIME type. Either case can lead to unexpected results, and if the content contains any user-controllable data may lead to cross-site scripting or other client-side vulnerabilities.

In most cases, the presence of an incorrect content type statement does not constitute a security flaw, particularly if the response contains static content. You should review the contents of the response and the context in which it appears to determine whether any vulnerability exists.

Issue remediation

For every response containing a message body, the application should include a single Content-type header which correctly and unambiguously states the MIME type of the content in the response body.

Request

GET /geo/util/js/country/ HTTP/1.1
Host: www.parallels.com
Proxy-Connection: keep-alive
Referer: http://www.parallels.com/
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.16 (KHTML, like Gecko) Chrome/10.0.648.204 Safari/534.16
Accept: */*
Accept-Encoding: gzip,deflate,sdch
Accept-Language: en-US,en;q=0.8
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3
Cookie: region=en|; __utmz=1.1302790956.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none); __utma=1.713730540.1302790956.1302790956.1302790956.1; __utmc=1; __utmb=1.1.10.1302790956

Response

HTTP/1.0 200 OK
Date: Thu, 14 Apr 2011 10:49:19 GMT
Server: Apache/2.2.3 (CentOS)
Expires: Fri, 15 Apr 2011 10:49:19 GMT
Content-Type: text/javascript
Age: 12793
Content-Length: 34
X-Cache: HIT from www.parallels.com
X-Cache-Lookup: HIT from www.parallels.com:80
Connection: keep-alive

window.GeoIP_country_code = 'US';
Report generated by XSS.CX at Thu Apr 14 14:18:06 CDT 2011.