Re: Stopping Arp poison attacks

["P. Entester" <pentest__ () hotmail com>]

Thank you all for your tips.

I now understand that Dynamic ARP inspection can prevent this technique in 
most cases.
However, this is vendor specific, and not every customer uses Cisco. Some 
Cisco switches like the 2950 for instance do not offer DAI (or DARP).

What kind of generic measures can be taken if DAI is not an option? Let's 
assume that the network is setup properly, with server, admin and user VLANS 
setup properly, and that i am doing a pentest, having access to important 
DMZ's.

Thanks in advance for your thoughts.


> From: Cedric Blancher <blancher () cartel-securite fr>
> To: "P. Entester" <pentest__ () hotmail com>
> CC: pen-test () securityfocus com
> Subject: Re: Stopping Arp poison attacks
> Date: Sat, 03 Jun 2006 18:00:18 +0200
>
> Le jeudi 01 juin 2006 à 08:14 +0000, P. Entester a écrit :
> > If i recommend our customers to bind the MAC addresses of mission 
> critical
> > servers' network interfaces to their respective ports on the routers and
> > switches, does that migitate most of the threat or am i missing 
> something
> > important?
>
> No, that does not mitigate the issue. What you're missing is that ARP
> cache poisoning does not change host MAC address, but the association
> between a MAC address and an IP address in ARP cache.
>
> In addition to pointers that were already given, you can try this one
> for ARP cache poisoning understanding:
>
>         http://sid.rstack.org/arp-sk/
>
> One other mitigation technic is static ARP cache entries, but it can
> become painful to maintain quite fast as network grows.
>
>
> --
> http://sid.rstack.org/
> PGP KeyID: 157E98EE FingerPrint: FA62226DA9E72FA8AECAA240008B480E157E98EE
> >> Hi! I'm your friendly neighbourhood signature virus.
> >> Copy me to your signature file and help me spread!

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