Re: usual iploggers miss some variable stealth scans

From: Andrea Gho (nailtbtat_private)
Date: Thu Jan 20 2000 - 11:24:58 PST

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    Well, about iplogging the fact is not that some iplogger can miss
    this specific sub-Xmas scans. The ''bug'' (if we can call it as a bug)
    it's at the base idea of many iploggers used nowadays is based on a
    concept:
    
    By default all packets passes
    Strange packets are logged.
    
    That's not the best, absolutely...
    In this situation every new scan require a source code modification and/or
    a reconfiguration of the tool.
    Some iploggers, instead, use a improved idea:
    
    By default all packets are logged
    Normal packets can pass
    
    And this can permit us not to rewrite pieces of code (and before tool
    update, miss this scan).
    
    			Nail
    
    
    ----------------------------------------
    
    Because sprintf and vsprintf assume an infinitely  long  string,
    callers  must  be careful not to overflow the actual space;
    this is often impossible to assure.
    					--- Linux man
    
    
    On Mon, 17 Jan 2000, vecna wrote:
    
    > in November`99 more or less... i've discovered 5 type of new stealth scan,
    > with the modification of flags used normally on XMAS stealth scan.
    >
    > the five type of packets that can be used for stealth scanning, and isn't
    > logged from the normal tcplogd/scanlogger have this flag:
    > URG
    > PUSH
    > URG+FIN
    > PUSH+FIN
    > URG+PUSH
    >
    > this flag on packet, such FIN, XMAS (fin+urg+psh), and NULL scan (no one
    > flag set) cause the reply RST+ACK if port is closed, and no reply if
    > port is open. this is efective only against *nix system
    >
    > i don't think that is an important tecnical notice... but most tcp logger
    > must be upgraded/reconfigurated.
    >
    > i've coded patch for nmap-2.12, check http://vecna.unix.kg
    >
    > Bye.
    > vecna
    >
    



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