RE: Using ARP to map a network

From: Rob Shein (shotenat_private)
Date: Wed Feb 05 2003 - 10:48:55 PST

  • Next message: Rob Shein: "RE: PBX Security"

    The only way to truly passively map a network, the term "passive" meaning
    you initiate nothing, is to be on the network, listening.  And any machine
    that does not send traffic onto your local wire (be it a VLAN, hub, your
    port on the switch, or whatever) will not show up.  This is why people still
    use active (and much more detectable) means to map networks.
    
    > -----Original Message-----
    > From: Jason Lewis [mailto:jlewisat_private] 
    > Sent: Tuesday, February 04, 2003 7:36 PM
    > To: pen-testat_private
    > Subject: RE: Using ARP to map a network
    > 
    > 
    > Maybe I am asking the wrong question.
    > 
    > If my goal is to passively map a network, what is the best 
    > way to do that?
    > 
    > > I'm not quite sure how ARP harvesting (via SNMP, presumably?) is 
    > > passive, but here goes:
    > >
    > > On the face of it, you should be able to do this.  Problems could 
    > > occur if you run into firewalls, or in switched environments where 
    > > there are machines that infrequently communicate outwards 
    > (and rarely 
    > > broadcast). Unfortunately, both of these instances are much more 
    > > likely with respect to critical infrastructure (like 
    > database back-end 
    > > servers or the accounting department.)  What is the goal of 
    > using this 
    > > means as opposed to some other method?  SNMP queries to 
    > routers may be 
    > > just as obvious as ping sweeps or SYN scans in the eyes of 
    > an IDS, and 
    > > perhaps even more so if they have logging set high enough.
    > >
    > >> -----Original Message-----
    > >> From: Jason Lewis [mailto:jlewisat_private]
    > >> Sent: Tuesday, February 04, 2003 6:37 PM
    > >> To: pen-testat_private
    > >> Subject: Using ARP to map a network
    > >>
    > >>
    > >> I have searched and can't seem to find any tools to help map a 
    > >> network based on ARP tables.
    > >>
    > >> It seems to me, I could take ARP tables from several machines and 
    > >> build a network map.  If machines were behind a router the 
    > ARP tables 
    > >> would show multiple IP's with the same MAC. With enough 
    > ARP tables, 
    > >> wouldn't I be able to build a map?
    > >>
    > >> Is my theory flawed?
    > >>
    > >> My goal is to do passive network mapping based on any local 
    > >> information I can obtain from computers or network devices. Anyone 
    > >> have any ideas?
    > >>
    > >> jas
    > >>
    > >>
    > >>
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    > 
    > 
    > 
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