ecb.europa.eu, XSS, Cross Site Scripting, CWE-79, CAPEC-86

Cross Site Scripting in ECB | Vulnerability Crawler Report

Report generated by XSS.CX at Fri Dec 31 12:09:54 CST 2010.

Contents

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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.ecb.europa.eu
Path:   /home/html/search.en.html

Issue detail

The name of an arbitrarily supplied request parameter is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 95e96"-alert(1)-"b1ad6edc6df 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 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.

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: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 /home/html/search.en.html?95e96"-alert(1)-"b1ad6edc6df=1 HTTP/1.1
Host: www.ecb.europa.eu
Proxy-Connection: keep-alive
Referer: http://www.ecb.int/home/html/researcher.en.html
Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.10 (KHTML, like Gecko) Chrome/8.0.552.224 Safari/534.10
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: Fri, 31 Dec 2010 17:49:03 GMT
Server: Apache/2.2.3 (Linux/SUSE)
X-Powered-By: PHP/5.2.5
Content-Type: text/html
Content-Language: en
Content-Length: 15259

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">

<head>
   <title>ECB: Search
...[SNIP]...
<script type="text/javascript">
var xajaxRequestUri="http://www.ecb.europa.eu/home/html/search.en.html?95e96"-alert(1)-"b1ad6edc6df=1";
var xajaxDebug=false;
var xajaxStatusMessages=false;
var xajaxWaitCursor=true;
var xajaxDefinedGet=0;
var xajaxDefinedPost=1;
var xajaxLoaded=false;
function xajax_storeSearchedItem(){return xajax
...[SNIP]...
2. Cross-domain script include  previous  next

Summary

Severity:   Information
Confidence:   Certain
Host:   http://www.ecb.europa.eu
Path:   /home/html/search.en.html

Issue detail

The response dynamically includes the following script from another domain:

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 /home/html/search.en.html HTTP/1.1
Host: www.ecb.europa.eu
Proxy-Connection: keep-alive
Referer: http://www.ecb.int/home/html/researcher.en.html
Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.10 (KHTML, like Gecko) Chrome/8.0.552.224 Safari/534.10
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: Fri, 31 Dec 2010 17:43:47 GMT
Server: Apache/2.2.3 (Linux/SUSE)
X-Powered-By: PHP/5.2.5
Content-Type: text/html
Content-Language: en
Content-Length: 15228

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">

<head>
   <title>ECB: Search
...[SNIP]...
</script>

<script src="http://www.google.com/jsapi?key=ABQIAAAAoMo6WJ3dgVqKBP-DYIygbhQYXQHHZL-thu4PQ3cHiePES4TKIBQvSqs4mtUjuMEh6wUrMqy6Y6xNmg" type="text/javascript"></script>
...[SNIP]...
3. Email addresses disclosed  previous

Summary

Severity:   Information
Confidence:   Certain
Host:   http://www.ecb.europa.eu
Path:   /shared/js/jquery.cookie.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 /shared/js/jquery.cookie.js HTTP/1.1
Host: www.ecb.europa.eu
Proxy-Connection: keep-alive
Referer: http://www.ecb.europa.eu/home/html/search.en.html
Accept: */*
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.10 (KHTML, like Gecko) Chrome/8.0.552.224 Safari/534.10
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: Fri, 31 Dec 2010 17:43:50 GMT
Server: Apache/2.2.3 (Linux/SUSE)
Last-Modified: Tue, 01 Apr 2008 14:52:45 GMT
ETag: "13401d-1096-449d0ebcdc940"
Accept-Ranges: bytes
Content-Length: 4246
Content-Type: text/x-js

/**
* Cookie plugin
*
* Copyright (c) 2006 Klaus Hartl (stilbuero.de)
* Dual licensed under the MIT and GPL licenses:
* http://www.opensource.org/licenses/mit-license.php
* http://www.gnu.org/li
...[SNIP]...
kie will be set and the cookie transmission will
* require a secure protocol (like HTTPS).
* @type undefined
*
* @name $.cookie
* @cat Plugins/Cookie
* @author Klaus Hartl/klaus.hartl@stilbuero.de
*/

/**
* Get the value of a cookie with the given name.
*
* @example $.cookie('the_cookie');
* @desc Get the value of a cookie.
*
* @param String name The name of the cookie.
* @return The value of the cookie.
* @type String
*
* @name $.cookie
* @cat Plugins/Cookie
* @author Klaus Hartl/klaus.hartl@stilbuero.de
*/
jQuery.cookie = function(name, value, options) {
if (typeof value != 'undefined') { // name and value given, set cookie
options = options || {};
if (value === null) {

...[SNIP]...
Report generated by XSS.CX at Fri Dec 31 12:09:54 CST 2010.