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

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

Report generated by CloudScan Vulnerability Crawler at Fri Feb 25 15:18:29 CST 2011.

Public Domain Vulnerability Information, Security Articles, Vulnerability Reports, GHDB, DORK Search

1. Cross-site scripting (reflected)

2. Cross-domain POST

3. Cross-domain script include

1. Cross-site scripting (reflected) next

Summary

Severity:	High
Confidence:	Certain
Host:	http://www.thecounter.com
Path:	/

Issue detail

The name of an arbitrarily supplied request parameter is copied into an HTML comment. The payload 6955f--><script>alert(1)</script>e525c47aab4 was submitted in the name of an arbitrarily supplied request parameter. This input was echoed unmodified in the application's response.

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

Remediation detail

Echoing user-controllable data within HTML comment tags does not prevent XSS attacks if the user is able to close the comment or use other techniques to introduce scripts within the comment context.

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 defenses:

Input should be validated as strictly as possible on arrival, given the kind of content which it is expected to contain. For example, personal names should consist of alphabetical and a small range of typographical characters, and be relatively short; a year of birth should consist of exactly four numerals; email addresses should match a well-defined regular expression. Input which fails the validation should be rejected, not sanitised.
User input should be HTML-encoded at any point where it is copied into application responses. All HTML metacharacters, including < > " ' and =, should be replaced with the corresponding HTML entities (< > etc).

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 /?6955f--><script>alert(1)</script>e525c47aab4=1 HTTP/1.1
Host: www.thecounter.com
Accept: */*
Accept-Language: en
User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0)
Connection: close

Response

HTTP/1.1 200 OK
Date: Fri, 18 Feb 2011 15:00:56 GMT
Server: Apache
Connection: close
Content-Type: text/html
Content-Length: 41197

<html>
<head>
<title>TheCounter.com - The Affordable Web Site Analysis Tool</title>


<LINK REL="stylesheet" HREF="/css/text.css" TYPE="text/css">
<meta http-equiv="Content-Type" con
...[SNIP]...
<script>alert(1)</script>e525c47aab4=1 -->
...[SNIP]...

2. Cross-domain POST previous next

Summary

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

Issue detail

The page contains a form which POSTs data to the domain search.internet.com. The form contains the following fields:

IC_Summary
IC_StartNumber
IC_BatchSize
IC_RelevanceThreshold
IC_QueryDatabase
IC_QueryText
SUBMIT

Issue background

The POSTing of data between domains does not necessarily constitute a security vulnerability. You should review the contents of the information that is being transmitted between domains, and determine whether the originating application should be trusting the receiving domain with this information.

Request

GET / HTTP/1.1
Host: www.thecounter.com
Accept: */*
Accept-Language: en
User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0)
Connection: close

Response

HTTP/1.1 200 OK
Date: Fri, 18 Feb 2011 15:00:55 GMT
Server: Apache
Connection: close
Content-Type: text/html
Content-Length: 40982

<html>
<head>
<title>TheCounter.com - The Affordable Web Site Analysis Tool</title>


<LINK REL="stylesheet" HREF="/css/text.css" TYPE="text/css">
<meta http-equiv="Content-Type" con
...[SNIP]...
</p>
<form method="POST" action="http://search.internet.com/www.jupiterweb.com" target="_top">
<input type="HIDDEN" name="IC_Summary" value="1">
...[SNIP]...

3. Cross-domain script include previous

Summary

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

Issue detail

The response dynamically includes the following scripts from other domains:

http://e1.cdn.qnsr.com/cgi/d/0/0/203/658830/cmp0.js
http://e1.cdn.qnsr.com/jsc/e1/fc.js
http://e1.cdn.qnsr.com/jsc/e1/fx.js

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.thecounter.com
Accept: */*
Accept-Language: en
User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0)
Connection: close

Response

HTTP/1.1 200 OK
Date: Fri, 18 Feb 2011 15:00:55 GMT
Server: Apache
Connection: close
Content-Type: text/html
Content-Length: 40982

<html>
<head>
<title>TheCounter.com - The Affordable Web Site Analysis Tool</title>


<LINK REL="stylesheet" HREF="/css/text.css" TYPE="text/css">
<meta http-equiv="Content-Type" con
...[SNIP]...
</SCRIPT><script language="javascript" src="http://e1.cdn.qnsr.com/cgi/d/0/0/203/658830/cmp0.js"></script>
<script language="javascript" src="http://e1.cdn.qnsr.com/jsc/e1/fx.js"></script>
<script language="JavaScript" src="http://e1.cdn.qnsr.com/jsc/e1/fc.js"></script>
...[SNIP]...

Report generated by CloudScan Vulnerability Crawler at Fri Feb 25 15:18:29 CST 2011.