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

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

Report generated by XSS.CX at Sun Apr 17 09:23:22 CDT 2011.

XSS.CX Research investigates and reports on security vulnerabilities embedded in Web Applications and Products used in wide-scale deployment.

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1. Cross-site scripting (reflected)

2. Cross-domain script include

3. Email addresses disclosed


1. Cross-site scripting (reflected)  next

Summary

Severity:   High
Confidence:   Certain
Host:   http://www.kirtsy.com
Path:   /submit.php

Issue detail

The name of an arbitrarily supplied request parameter is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload fc309"><img%20src%3da%20onerror%3dalert(1)>f2948ed7988 was submitted in the name of an arbitrarily supplied request parameter. This input was echoed as fc309\"><img src=a onerror=alert(1)>f2948ed7988 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 PoC attack demonstrated uses an event handler to introduce arbitrary JavaScript into the document.

Note that a redirection occurred between the attack request and the response containing the echoed input. It is necessary to follow this redirection for the attack to succeed. When the attack is carried out via a browser, the redirection will be followed automatically.

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.

Issue remediation

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 /submit.php?fc309"><img%20src%3da%20onerror%3dalert(1)>f2948ed7988=1 HTTP/1.1
Host: www.kirtsy.com
Accept: */*
Accept-Language: en
User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0)
Connection: close

Response (redirected)

HTTP/1.1 200 OK
Date: Sun, 17 Apr 2011 14:14:12 GMT
Server: Apache/2.0.63 (Unix) mod_ssl/2.0.63 OpenSSL/0.9.8e-fips-rhel5 mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635 PHP/5.2.13
X-Powered-By: PHP/5.2.13
Connection: close
Content-Type: text/html
Content-Length: 20799


<!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" xml:lang="en" lang="en">

...[SNIP]...
<input type="hidden" name="return" value="/submit.php?fc309\"><img src=a onerror=alert(1)>f2948ed7988=1"/>
...[SNIP]...
2. Cross-domain script include  previous  next

Summary

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

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 /a HTTP/1.1
Host: www.kirtsy.com
Proxy-Connection: keep-alive
Referer: http://www.kirtsy.com/login.php?return=/submit.php?fc309%22%3E%3Cimg%20src%3da%20onerror%3dalert(document.cookie)%3Ef2948ed7988=1
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: mobify=0

Response

HTTP/1.1 404 Not Found
Date: Sun, 17 Apr 2011 14:21:51 GMT
Server: Apache/2.0.63 (Unix) mod_ssl/2.0.63 OpenSSL/0.9.8e-fips-rhel5 mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635 PHP/5.2.13
X-Powered-By: PHP/5.2.13
Content-Type: text/html
Content-Length: 19540


<!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" xml:lang="en" lang="en">

...[SNIP]...
<!-- FM Medium Rectangle Zone -->
<script type='text/javascript' src='http://static.fmpub.net/zone/2767'></script>
...[SNIP]...
<!-- FM Wide Skyscraper Zone -->
<script type='text/javascript' src='http://static.fmpub.net/zone/2768'></script>
...[SNIP]...
<link href="https://youdata_adgets.s3.amazonaws.com/overlay_kirtsy.css" rel="stylesheet" type="text/css">
<script src='https://youdata_adgets.s3.amazonaws.com/YouDataAdget.js' type='text/javascript'></script>
...[SNIP]...
<!-- FM Leaderboard Zone -->
<script type='text/javascript' src='http://static.fmpub.net/zone/2769'></script>
...[SNIP]...
<!-- FM Tracking Pixel -->
<script type='text/javascript' src='http://static.fmpub.net/site/kirtsy'></script>
...[SNIP]...
<!-- Start Quantcast tag -->
<script type="text/javascript" src="http://edge.quantserve.com/quant.js"></script>
...[SNIP]...
3. Email addresses disclosed  previous

Summary

Severity:   Information
Confidence:   Certain
Host:   http://www.kirtsy.com
Path:   /modules/niftycube/js/niftycube.js

Issue detail

The following email address was disclosed in the response:

Issue background

The presence of email addresses within application responses does not necessarily constitute a security vulnerability. Email addresses may appear intentionally within contact information, and many applications (such as web mail) include arbitrary third-party email addresses within their core content.

However, email addresses of developers and other individuals (whether appearing on-screen or hidden within page source) may disclose information that is useful to an attacker; for example, they may represent usernames that can be used at the application's login, and they may be used in social engineering attacks against the organisation's personnel. Unnecessary or excessive disclosure of email addresses may also lead to an increase in the volume of spam email received.

Issue remediation

You should review the email addresses being disclosed by the application, and consider removing any that are unnecessary, or replacing personal addresses with anonymous mailbox addresses (such as helpdesk@example.com).

Request

GET /modules/niftycube/js/niftycube.js HTTP/1.1
Host: www.kirtsy.com
Proxy-Connection: keep-alive
Referer: http://www.kirtsy.com/login.php?return=/submit.php?fc309%22%3E%3Cimg%20src%3da%20onerror%3dalert(document.cookie)%3Ef2948ed7988=1
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

Response

HTTP/1.1 200 OK
Date: Sun, 17 Apr 2011 14:21:46 GMT
Server: Apache/2.0.63 (Unix) mod_ssl/2.0.63 OpenSSL/0.9.8e-fips-rhel5 mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635 PHP/5.2.13
Last-Modified: Sun, 28 Dec 2008 05:32:24 GMT
ETag: "1f78266-21ef-45f14aed4aa00"
Accept-Ranges: bytes
Content-Length: 8687
Content-Type: application/javascript

/* Nifty Corners Cube - rounded corners with CSS and Javascript
Copyright 2006 Alessandro Fulciniti (a.fulciniti@html.it)

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the Licens
...[SNIP]...
Report generated by XSS.CX at Sun Apr 17 09:23:22 CDT 2011.