Re: Syn packets hitting port 80, not webserver

From: Neil Dickey (neilat_private)
Date: Fri Sep 28 2001 - 13:30:01 PDT

  • Next message: Chad Mawson: "ssh scans"

    Richard.Smithat_private wrote:
    
    >If you see just the syn packet you are not going to match a signature 
    >against Nimda or any other exploit for that matter because you have not 
    >captured the packet.
    
    Thanks, Richard.  Some of the others don't seem to have realized that's
    why I asked the question -- that, and because while CR and Nimda hits
    against all my other machines have tailed off to very low levels, the
    pressure against this one, of whatever sort, has remained constant.
    
    Also, I opened port 80, though I didn't set up a web-server, while
    running tcpdump, against the possibility that the blocking software might
    interfere with what I wanted to see.  I wasn't clear about that in my
    original post, and I apologize.
    
    Marc:  I checked the DNS entries, and at least our local DNS servers
    don't have errors in them.  There are no web-server addresses which
    resolve to this box.
    
    Xno:  Thanks for your explanation.  I think that may be what's happening.
    The assymetry in hits is perhaps due to non-random generation of target
    IPs by whatever worm is responsible.
    
    Best regards,
    
    Neil Dickey, Ph.D.
    Research Associate/Sysop
    Geology Department
    Northern Illinois University
    DeKalb, Illinois
    60115
    
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