Bypassing website filter in SonicWall

From: Marc Ruef (marc.ruefat_private)
Date: Tue Oct 29 2002 - 11:36:24 PST

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    Hi!
    
    I found a little weakness in SonicWall: I turn on the blocking
    mechanism for websites (e.g. www.google.com). Now I can't reach
    the website using the domainname. But if I choose the IP address of the
    host (e.g. http://216.239.53.101/), I can contact the forbidden
    website. The same issue I've discovered for NetGear FM114P in
    http://online.securityfocus.com/bid/5667
    
    It would make sense if you can do an internal nslookup. Otherwise the
    user can do a workaround and adding always the ip address(es) of the
    blocked websites. But this can cause some problems if there were some
    virtual hostings. A smart attacker can use some dottless-ips to bypass
    the new workaround IP filter. The box will sadly loose performance
    because of the additional filter line(s).
    
    My description was sent on 02/10/15 to infoat_private - No response
    came back. The blocking URL message style and problem reminds my the
    website blocking mechanism by NetGears FM114P. It could be that both
    use the same mechanism (by a 3rd party?). So, if the bug is fixed for
    one box the other will also be fixed - I think so.
    
    Bye, Marc
    
    -- 
    Computer, Technik und Security
    http://www.computec.ch
    



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