Snort mailing list archives

Re: Tcp session hijacking


From: Meysam Farazmand <farazmand.meisam () gmail com>
Date: Tue, 19 Aug 2014 22:34:02 +0430

Hi Waldo,

My testing network consists of four pc and an unmanaged switch and i don't
have any router. As i said before, i poisioned all of pc and switch arp
tables with "ettercap".so, when bening pc make a tcp connection to snort pc
and we poision its arp tables, the source mac address changes to mac
address of attacker and i expect, snort detect this changing.
On Aug 19, 2014 10:23 PM, "waldo kitty" <wkitty42 () windstream net> wrote:


top posting "corrected" to inline for readability... see my reply below...

On 8/19/2014 1:00 PM, Meysam Farazmand wrote:
On Aug 19, 2014 9:11 PM, "Jefferson, Shawn" <
Shawn.Jefferson () bcferries com> wrote:

    Wouldn’t your MAC addresses just be those of your routers anyway?
Any
    non-trivial network (ie. Enterprise) probably won’t get much
benefit from
    Snort trying to detect this.  You’re better off using the anti-mac
spoofing
    features of your switches, IMO.____

Hi Jefferson,

When we do a man in the middle attack, all of devices arp tables updates
with
mac address of attacker. So this changes in mac address should be detect
as
session hijacking with stream5 preprocessor. Because stream5
check_session_hijacking option rely on changes in mac address of a tcp
connection.

i think that what jefferson is attempting to point out is that MAC
addresses are
only good on the current link... in other words, this chart shows 3 MAC
address
changes in the flow of traffic from A to B...

     A -> router1 -> router2 -> B

and this one shows 5 changes...

     A -> router1 -> router2 -> router3 -> router4 -> B

the source MAC and destination MAC inside the packet will change at each
"->"...
IIRC, this is the same for hubs and switches, too...

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