RE: Unauthorised switchport access

["Erick Jensen" <ejensen () vibrant com>]

In a short answer, yes, you are at risk.  But how much risk?  That's up
to you.

If you shutdown unused ports, that would help.  But that would only
allow a MITM attack on an active port.  You could then bind the MAC
address of the 'trusted' machine to the port.  That means they would
have to spoof the MAC, which is do-able.  

To secure beyond all of that you would need something else in place.
For example, IPsec across the network.  I think you have to decide
what's at risk and weigh out the options.  

I think your easiest, most reliable fix would be locks on the wiring
closets.

Something you can try?  Get Cain & Able and arp poison the network to
sniff the traffic on a switched network.  It's quick and simple, and
proof you are at risk.  If everything was encrypted, that would a
useless test.

Erick



-----Original Message-----
From: listbounce () securityfocus com [mailto:listbounce () securityfocus com]
On Behalf Of gary.shaw () dfpni gov uk
Sent: Tuesday, November 14, 2006 3:36 AM
To: security-basics () securityfocus com
Subject: Unauthorised switchport access

Guys

I am responsible for several LANs that include sharing WCs with other
organisations, and therefore access to my 3750 switches in unlocked
cabinets. 
I have no port security enabled and the ports are not shut down. 
I would like to know the security implications of having unused
switchports available to anyone eg with a laptop & DHCP configured? 
Are there any simple pentests i could complete myself?
Is my organisation's network a sitting duck??
Thanks in advance!

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