Cross-domain redirect on RSA Authentication Agent
05 December 2007
13 December 2007
Richard Brain of ProCheckUp Ltd (www.procheckup.com). ProCheckUp thanks RSA for being so cooperative and responding so fast.
A remote URI redirection vulnerability affects the RSA Authentication Agent. This issue is due to a failure of the application to properly sanitize URI-supplied data assigned to the 'url' parameter.
An attacker may leverage this issue to carry out convincing phishing attacks against unsuspecting users by causing an arbitrary page to be loaded once a RSA Authentication Agent specially-crafted URL is visited.
Although the 'url' parameter is filtered for protocol URLs such as 'http://' and 'https://', is NOT filtered for other protocols such as FTP or Gopher. An attacker could upload a spoof login page to a FTP server that allows anonymous connections where the victim would be redirected.
Vulnerable server-side program: '/WebID/IISWebAgentIF.dll'
Unfiltered parameter: 'url'
Victim users can be redirected to third-party sites for the purpose of exploiting browser vulnerabilities or performing phishing attacks.
the redirect will only take place in browsers which consider URLs with only one slash after the colon symbol ':' as valid when performing redirects - i.e.: "Location: ftp:/evil-domain.foo/"
Successfully tested on
RSA Authentication Agent 184.108.40.2068 for Web for Internet Information Services in conjunction with Mozilla Firefox 220.127.116.11
Proof of concept:
Example of specially-crafted URL:
COMPLETE HTTP REQUEST:
GET /WebID/IISWebAgentIF.dll?Redirect?url=ftp://bo.mirror.garr.it/pub/mirrors/Mandrake/devel/cooker/i586/index.htm HTTP/1.1
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.0; en-GB; rv:18.104.22.168) Gecko/20071127 Firefox/22.214.171.124
COMPLETE HTTP RESPONSE:
HTTP/1.x 302 Object Moved
Date: Tue, 18 Dec 2007 09:35:19 GMT
How to fix:
The vendor has stated that this issue was addressed in the RSA Authentication Agent 126.96.36.1998. RSA customers can download the upgrade from the RSA web site.
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