Re: FireWall-1 FTP Server Vulnerability

From: Dug Song (dugsongat_private)
Date: Fri Feb 18 2000 - 20:27:26 PST

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    On Fri, 18 Feb 2000, Mikael Olsson wrote:
    
    > The only solution that even begins to look "good" is to completely
    > reassemble the TCP stream and not make "educated" guesses about what
    > packet data belongs on what line and in which order and state of the
    > FTP protocol.
    
    inspecting TCP application data within individual IP packets is a basic
    layer violation. network IDSs also suffer from this problem, only worse.
    fragrouter demonstrates this nicely.
    
    reassembling the TCP stream will only get you so far - your proxy still
    needs to actually implement the application protocol correctly. i'm
    releasing a 'fragproxy' tool soon to demonstrate this.
    
    but for now, an ObLameExploit:
    
    	http://www.monkey.org/~dugsong/ftp-ozone.c.txt
    
    -d.
    
    ---
    http://www.monkey.org/~dugsong/
    



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