Security Basics mailing list archives
RE: inter-site WAN security question
From: "Dan Denton" <ddenton () remitpro com>
Date: Thu, 5 Jul 2007 14:29:31 -0500
In the case of cisco pix VPN's, the firewalls are supplied the ip address of the peer device, an encryption key (password), algorithms and hashes, and a few other bits of info. If those things are the same on both ends, the tunnel is established. Of course there's more to it than this, but no other pathing info is needed. As long as the internet connectivity is there, and the routing is working, the rest is in the details and setup. As far as the ability to sniff, all the traffic should be encrypted, not just some, so anyone performing a MIM shouldn't be able to pick out pertinent info from the stream without breaking the encryption. -----Original Message----- From: listbounce () securityfocus com [mailto:listbounce () securityfocus com] On Behalf Of nobledark () hushmail com Sent: Wednesday, July 04, 2007 6:15 PM To: Security Basics Forum Subject: Re: inter-site WAN security question Hi Andrew, thanks for the quick reply.. So if I understand you correctly, if someone were sniffing on a router between the two sites and the VPN was in tunnel mode then they would not be able to see the source and destination IP's - is that correct? Sorry, a bit ignorant about the inner workings of IPSEC VPNs...what about during the initial tunnel establishment - how does the vpn server at s1 know the path to the vpn server at s2? Thanks again... On Wed, 04 Jul 2007 15:33:06 -0400 Andrew Harris <andrew.f.harris () gmail com> wrote:
The question you want answered is based on the implementation of the VPN. If the VPN is using IPSec's Tunnel mode, headers & the payload are encrypted/encapsulated. If just using Transport mode, only the payload is encapsulated so the IP appear in plaintext. So to answer your question, if using Transport mode, then the hacker would be able to see the that S1 and S2 are in communication. In Tunnel mode, the hacker would have a very hard time and then the weakness of the security lies in the IPSec encryption itself (how long it takes to crack that...). Hope this helps On 7/4/07, nobledark () hushmail com <nobledark () hushmail com> wrote:Hi, 1st post - I had a hypothetical question poised to me that Icouldnot answer so I thought that I would ask the list. Here's the scenario: - Two sites, s1 and s2 - s1 and s2 have the need for a bi-directional WAN link - The WAN link would be secured via a VPN and all traffic wouldbetunneled through the VPN - Both sites are connected via broadband links; s1 is on a cable modem and s2 utilizes a factional T-1. - There are 5 hops between s1 and s2. Given this scenario, the question was, how anonymous can the connection be between these sites? Put a different way, assuming that s1 and s2 are secure and not under hacker control, how much
ofa threat is there of a 3rd party monitoring the traffic streamoverthe route between the sites and discovering that they aretalkingto each other? Thanks.... -- Discount Online Trading - Click Now!http://tagline.hushmail.com/fc/Ioyw6h4dPYvV4GSzCfyZF7HOo0xdrbO1a8xm
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Current thread:
- inter-site WAN security question nobledark (Jul 04)
- Re: inter-site WAN security question Ansgar -59cobalt- Wiechers (Jul 04)
- <Possible follow-ups>
- Re: inter-site WAN security question nobledark (Jul 05)
- RE: inter-site WAN security question David Gillett (Jul 05)
- RE: inter-site WAN security question Dan Denton (Jul 05)
- Re: inter-site WAN security question Dathan Bennett (Jul 05)
- Re: inter-site WAN security question Ansgar -59cobalt- Wiechers (Jul 06)
- Re: inter-site WAN security question Joseph Brown (Jul 06)
- Re: inter-site WAN security question Ansgar -59cobalt- Wiechers (Jul 06)