Security Basics mailing list archives
RE: Very Strange Incident
From: "Shawn Jackson" <sjackson () horizonusa com>
Date: Tue, 23 Mar 2004 08:23:16 -0800
VPN packet dropped (100R->Vraptor: Protocol=IPSEC-ESP spi=0x4ac80658): The packet is either too old or has been received before (potential replay attack?) (tunnel 6.isakmp.104@100r <VPN-100r>)
When working on larger WAN's with IPSEC connected sites I've received that message if one of the remote VPN terminators clock is off by too much time. Usually I setup my NS servers (NS1, NS2, NS3) with NTPd and have them sync with some teir1 and tier2 NTP providers, then have all my equipment point To them.
As the Cisco was the last hop before the subnet I can't think why
traceroutes
would be redirected to this new device. Especially as only the ISP has
access
to the router to make config changes
I don't think it's likely that there is a device trying to 'hack' your VPN tunnel. At the very least, it could just be too much lag between the remote side VPN and the VPN core. It could also be a malfunctioning router which is holding packets in it's transfer cache for too long. But get info on that device, and slap your IT guy. Can never be too careful. Shawn Jackson Systems Administrator Horizon USA 1190 Trademark Dr #107 Reno NV 89521 www.horizonusa.com Email: sjackson () horizonusa com Phone: (775) 858-2338 (800) 325-1199 x338 --------------------------------------------------------------------------- Ethical Hacking at the InfoSec Institute. Mention this ad and get $545 off any course! All of our class sizes are guaranteed to be 10 students or less to facilitate one-on-one interaction with one of our expert instructors. Attend a course taught by an expert instructor with years of in-the-field pen testing experience in our state of the art hacking lab. Master the skills of an Ethical Hacker to better assess the security of your organization. Visit us at: http://www.infosecinstitute.com/courses/ethical_hacking_training.html ----------------------------------------------------------------------------
Current thread:
- Very Strange Incident Alan Greig (Mar 22)
- <Possible follow-ups>
- RE: Very Strange Incident Shawn Jackson (Mar 23)