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Date:      Sat, 21 Apr 2001 16:56:20 +0700
From:      Igor Podlesny <poige@morning.ru>
To:        freebsd-security@FreeBSD.ORG
Subject:   Re[2]: static arp values
Message-ID:  <1972094846.20010421165620@morning.ru>

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PT> On Fri, 20 Apr 2001, Joseph Gleason wrote:

>> When you do arp -a, is the static entry you set marked as permanent?

PT> yes it is

>> 
>> Did you simulate anouther box taking that IP and look at the arp table
>> afterward?
>> 

PT> Yes I did. And the arp is infact what it is suppose to be. So it appear
PT> static. (when i did the same thing on w2k, arp -s, the mac adress 
PT> changed).
PT> But I can still sniff the connection between the machine with the static
PT> arp value and the router. That is what I find strange.

hm.  it  seems  you need to know how ETHERNET networks work. No matter
does  a  box  know MAC.addr of other box or it asks network for it. At
last,  they  will  talk to each other over SHARED media which ETHERNET
certainly  is. You may use `Switches' to avoid such situation, some of
them  can  be  even  configured  to bind their ports to respective MAC
addrs,  but  some  cards  can  be  MAC changeable, as "Joseph Gleason"
<clash@tasam.com>  mentioned before... In short, all these gotchas are
drawbacks of Ethernet technology. If you use it the only way to be 99%
protected is using of VPN technology over it.

good luck!

PT> I simulate the man-in-the-middle attack with ettercap by the way.


>> Also, you should be aware that some cards allow you to change the MAC
>> address of the card.  (At least I think so...never tried it)  So an evil
>> machine could steal the MAC address and fool the switch into sending it your
>> traffic.
>> 
>> Depending on how advanced your switch is and if it is managable, you can
>> hardcode what MAC address is on what port...avoid this one as well.
>> 
>> ----- Original Message -----
>> From: "Pär Thoren" <t98pth@student.bth.se>
>> To: <freebsd-security@FreeBSD.ORG>
>> Sent: Friday, April 20, 2001 13:13
>> Subject: static arp values
>> 
>> 
>> > Hi!
>> >
>> >
>> > Is it possible to make a arptable entry static? For example the arp adress
>> > of my gateway. So that man-in-the-middle attack can be prevented.
>> >
>> >
>> > I´ve tried "arp -S ip-adres mac-adres" but it seems that it is still
>> > possible to infect the arptable with a false mac adress of the gateway and
>> > sniff the connection.
>> >
>> >
>> > /Pär
>> >
>> >
>> >
>> > To Unsubscribe: send mail to majordomo@FreeBSD.org
>> > with "unsubscribe freebsd-security" in the body of the message
>> >
>> 
>> 
>> To Unsubscribe: send mail to majordomo@FreeBSD.org
>> with "unsubscribe freebsd-security" in the body of the message
>> 


PT> To Unsubscribe: send mail to majordomo@FreeBSD.org
PT> with "unsubscribe freebsd-security" in the body of the message



-- 
 Igor                            mailto:poige@morning.ru



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