Multiple Joomla! XSS Vulnerabilities – CVE-2010-1649

Last month, while doing some tests on a Joomla! installation on my home computer, I came across a very glaring security issue. The Joomla! admin module has several components that are used to manage the site and its users. Several of these components have a search text box that allows users to search through the list of entities displayed. For example the search box in com_users component allows searching the list of users displayed. The issue was with the search boxes not sanitizing user input. That meant you could enter HTML text in the boxes and it would be rendered and displayed! That is exactly the cause of the world’s most common web application vulnerability, Cross Site Scripting or more commonly known as XSS.

This should help beginners understand XSS.

Cross-site scripting (XSS) is a type of computer security vulnerability typically found in web applications that enables malicious attackers to inject client-side script into web pages viewed by other users. An exploited cross-site scripting vulnerability can be used by attackers to bypass access controls such as the same origin policy.

Their impact may range from a petty nuisance to a significant security risk, depending on the sensitivity of the data handled by the vulnerable site, and the nature of any security mitigation implemented by the site’s owner.

Attackers intending to exploit cross-site scripting vulnerabilities must approach each class of vulnerability differently. For each class, a specific attack vector is described here. The names below are technical terms, taken from the cast of characters commonly used in computer security.

Cross Site Scripting can be divided into 2 classes. Persistent and Non-Persistent. The following exploit examples should make things clearer:

Examples taken from Wikipedia.


1. Alice often visits a particular website, which is hosted by Bob. Bob’s website allows Alice to log in with a username/password pair and stores sensitive data, such as billing information.
2. Mallory observes that Bob’s website contains a reflected XSS vulnerability.
3. Mallory crafts a URL to exploit the vulnerability, and sends Alice an email, enticing her to click on a link for the URL under false pretenses. This URL will point to Bob’s website, but will contain Mallory’s malicious code, which the website will reflect.
4. Alice visits the URL provided by Mallory while logged into Bob’s website.
5. The malicious script embedded in the URL executes in Alice’s browser, as if it came directly from Bob’s server (this is the actual XSS vulnerability). The script can be used to send Alice’s session cookie to Mallory. Mallory can then use the session cookie to steal sensitive information available to Alice (authentication credentials, billing info, etc.) without Alice’s knowledge.

Persistent attack:

1. Mallory posts a message with malicious payload to a social network.
2. When Bob reads the message, Mallory’s XSS steals Bob’s cookie.
3. Mallory can now hijack Bob’s session and impersonate Bob.

All versions of Joomla! prior to 1.5.18 are vulnerable to an XSS injection attack in the admin module. The following are the vulnerabaility details and exploit code.

* Project: Joomla!
* SubProject: All
* Severity: High
* Versions: 1.5.17 and all previous 1.5 releases
* Exploit type: XSS Injection
* Reported Date: 2010-May-13
* Fixed Date: 2010-May-28
* Fixed Version: Joomla! 1.5.18
* Update Download Link:
* Info URL:

Vulnerability Details:

User can execute arbitrary JavaScript code within the vulnerable application.

The vulnerability arises due to the administrator core components failing to properly sanitize user-supplied input in the “search”
variable. Successful exploitation of this vulnerability could result in, but not limited to, compromise of the application, theft of cookie-based authentication credentials, arbitrary url redirection, disclosure or modification of sensitive data and phishing attacks.

An attacker can send a link with the exploit to an administrator whose access could compromise the application. The following PoC is





















BID: 40444 –
Secunia: 39964:
OSVDB: 65011:

Please update your installation of Joomla! to the latest available stable release, which at the time of writing was 1.5.18.