Re: PIX and ttl

From: Nelson Brito (nelsonat_private)
Date: Fri May 25 2001 - 13:51:47 PDT

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    Fernando Cardoso wrote:
    
    [...]
    
    > I don't think so... I've tested all kind of Windows stuff and I always get
    > 128 (local LAN). Maybe the results you're showing are the result of some
    > kind of "PIX tweaking".
    > 
    > > -- Windows NT 4.0 x86 SP6a ( ttl = 128 ) in MY LAN
    > > 46 bytes from 10.1.3.20: flags=SA seq=0 ttl=128 id=25884 win=8576
    > > rtt=0.5 ms
    
    It's the default setting in WinNT´s Registry, but you can set it up to
    whatever value you want, just editing your NT Box.
    
    I already post, some times ago, talking about ICMP Fingerprint.
    
    The registry key you need modify to confuse the attacker(maybe
    penetration tester ;)) is:
    [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters]
    "DefaultTTL"=dword:000000ff
    
    This means the TTL is now set to 255 or 0x000000ff in hex.
    
    So, I could set this value to 0x00000081(129 in decimal), so it would be
    weird when some attacker try to "traceroute" this host. What do you
    think? ;))
    
    PS: Sorry my poor English...
    
    Sem mais
    -- 
    # Nelson Brito
    # Security Analyst and Penetration Tester
    # Security Networks AG - The trust Company!
    #
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