Re: ICMP unreachable question

From: Penetration Testing (pentestat_private)
Date: Mon Oct 29 2001 - 09:30:22 PST

  • Next message: Ofir Arkin: "RE: ICMP unreachable question"

    On Fri, 26 Oct 2001, Steve Culligan wrote:
    
    > [snip]
    > 
    > So my question is , Can this be used as a denial of service attack to 
    > continually send these ICMP packets to a server to confuse it or bring it 
    > down.
    > Anybody had any experience with this or know any tools which can generate 
    > these ICMP reachable packets ?
    > 
    
    Steve,
    
    I think the ICMP that you are seeing is Type 3, Code 4.  It would be
    pretty easy to put together a little tool to generate these packets using
    libnet.
    
    As for whether this could be used for DoS, I guess that depends on the
    parameters/options.  If you can send through a packet telling the remote
    end to set its MTU to 0, then I imagine that it would effectively kill the
    connection.  This would, of course, rely on the ICMP making it past the
    firewall.
    
    Regards,
    Dave Taylor
    
    
    
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