Penetration Testing mailing list archives

Re: Risks associated to branch office IPSec devices


From: Matt Bellizzi <matt.bellizzi () nokia com>
Date: Tue, 21 Jun 2005 18:20:55 -0700

Hey Most VPN appliances have what are called selectors. I belive per RFC are bypass, encrypt or drop. If the traffic matches the selector then just like a firewall rule it will do what ever the selector specifys. If the IPSec gateway default is to bypass all non-encrypted traffic that would be bad. Personally if the VPN device is locked down properly and has anti spoofing code implemented and only allows udp 500 and AH or ESP I really see no need for a firewall as long as default behavior for non-ecrypted traffic is drop. As for the NAT portion are you talking about NAT before IPSec or are talking about VPN GW just NAT'ing out bound traffic that matches no encrypt selector?


Matt Bellizzi
Nokia Enterprise Systems
SQA Engineer IP VPN Group


ext Rodrigo Blanco wrote:

Hello list,

I have just come across a doubt about branch office VPN devices.
Normally, they are used so that a branch office's network - typically
with a private addressing scheme - can securely connect to the
headquarters' central network.

Such VPN devices normally do not include a firewall, so I was
wondering if this really represents a risk:

Yes - it is a risk if the VPN device just acts as a router (no ACLs)
and is attached to the Internet.
No - because the addressing scheme behind it is private, hence
non-routable, hence unreachable across the Internet (internet routers
would drop packets with such destinations?)

The only real risk I see is if the VPN device is cracked, and from
there the security of the whole network (both brach office and
headquarters) is exposed. Am I right?

Any ideas would be more than welcome. Thanks in advance for your
advice and best regards,

Rodrigo.




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