Have you played with any utilities that can modify the ttl to ensure that admins do not notice the decremented ttl? Just a suggestion. Aside from this, I consider it a very creative use of policy routing. It may actually be a bit more secure if you were to configure an IPsec connection (or Cisco's older IOS encryption if IPsec is not available) rather than/on top of GRE (which IS available on nearly all IOS revisions). Nice paper overall! -Jeremy -----Original Message----- From: Axel Dunkel [mailto:adat_private] Sent: Monday, July 15, 2002 11:52 AM To: Ryan_Moffettat_private Cc: pen-testat_private Subject: RE: Using a Compromised Router to Capture Network Traffic > Is this hosted on an alternate site other than the geocities site > which has exceeded the xfer limit? For a while, I have put it on http://www.Dunkel.de/download/GRE_sniffing.doc to help out. Best regards, Axel Dunkel > -----Original Message----- > From: Penetration Testing [mailto:pentestat_private] > Sent: Monday, July 15, 2002 2:44 PM > To: pen-testat_private > Subject: Using a Compromised Router to Capture Network Traffic > > > Hi all. > > I have recently completed some experimentation into using a captured > router to sniff network traffic on a remote network. This is in the > same vein as Gauis' article in Phrack 56 (Things to do in cisco land > when you are dead). > > I have tried to build on Gauis' work in that I terminated the GRE > tunnel on a Cisco router instead of a *nix machine. I explored a > couple of possible scenarios for this, the net result being that it is > possible to remotely capture (bi-directional) network traffic using NO > customised tools; all that is required is one cisco router with > vanilla IOS, and a machine that can run snoop or tcpdump. > > Anyway, if anyone is interested, the document describing the > experiment and results is available at > http://www.geocities.com/david_taylor_au/ > (Word 2000 format). Or, contact me. > > Regards, > Dave Taylor > > > ---------------------------------------------------------------------- > ------ > This list is provided by the SecurityFocus Security Intelligence Alert (SIA) > Service. For more information on SecurityFocus' SIA service which > automatically alerts you to the latest security vulnerabilities please see: > https://alerts.securityfocus.com/ > > ---------------------------------------------------------------------- > ------ > This list is provided by the SecurityFocus Security Intelligence Alert (SIA) > Service. For more information on SecurityFocus' SIA service which > automatically alerts you to the latest security vulnerabilities please see: > https://alerts.securityfocus.com/ > > --- Systemberatung A. Dunkel GmbH, Gutenbergstr. 5, D-65830 Kriftel Tel.: +49-6192-9988-0, Fax: +49-6192-9988-99, E-Mail: adat_private ------------------------------------------------------------------------ ---- This list is provided by the SecurityFocus Security Intelligence Alert (SIA) Service. For more information on SecurityFocus' SIA service which automatically alerts you to the latest security vulnerabilities please see: https://alerts.securityfocus.com/
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