[Snort-users] Tcp session hijacking

waldo kitty wkitty42 at ...14940...
Tue Aug 19 13:49:53 EDT 2014

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 at ...14448...> 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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