Re: FW: Remote Desktop vs. VPN on Windows 2003

[Nick Owen <nickowen () mindspring com>]

There is a tool for cracking PPTP - asleap - asleap.sourceforge.net.
Asleap was originally designed to crack passwords in LEAP passively on
WiFi Networks. It has been extended to PPTP. It is a MITM attack can be
done easily on a WiFi connection (unlike a wired MITM attack). 

So if you're using PPTP and can't be sure that your remote users aren't
logging in on a WiFi network, you should switch to IPSec or go with a
one-time password system. As I understand it, the weakness is in MS-CHAP
v2, I believe.  you can google for more info:
http://www.google.com/search?q=PPTP+password+cracker


On Fri, 2005-01-21 at 15:07 -1000, Jeff Randall wrote:
> Like the RC4 keys, are there any offline attacks available for cracking
> PPTP traffic?  To get either RDP or PPTP I assume you already have to
> have some sort of MITM/sniffing going on anyways.  Isn't the PPTP
> encryption algorithm (MPPE)40/128 bits as well?
>
> -----Original Message-----
> From: Conlan Adams [mailto:conlan () mebtc org] 
> Sent: Wednesday, January 19, 2005 12:10 PM
> To: Roger A. Grimes; security-basics () securityfocus com
> Subject: RE: Remote Desktop vs. VPN on Windows 2003
>
> Number of available cracks on SSH and RDP is not really related to
> strength of a protocol, only to the number of people looking at the
> code.
>
> SSH thousands of sets of eyes on the code.
>
> RDP only the eyes Microsoft allows.
>
> The RC4 encryption used by Microsoft for RDP is susceptible to offline
> attack just like WEP.  Long story short, someone can grab your traffic
> and crack at their leisure.
>
> Also, I can look into it as well, how many of the cracks against SSH are
> remote access?  Not local elevation of privileges, or Denial Of Service?
>
> Conlan Adams
>
>
>
> -----Original Message-----
> From: Roger A. Grimes [mailto:roger () banneretcs com]
> Sent: Wednesday, January 19, 2005 2:22 PM
> To: Ansgar -59cobalt- Wiechers; security-basics () securityfocus com
> Subject: RE: Remote Desktop vs VPN on Windows 2003
>
> SSH multiple hacks...RDP one in 2002.  How is RDP the worse tool?  I
> keep waiting for facts? 
>
> -----Original Message-----
> From: Ansgar -59cobalt- Wiechers [mailto:bugtraq () planetcobalt net]
> Sent: Wednesday, January 19, 2005 12:05 PM
> To: security-basics () securityfocus com
> Subject: Re: Remote Desktop vs VPN on Windows 2003
>
> On 2005-01-18 Roger A. Grimes wrote:
> > but if the Windows tool can do the same or better job, why not use the
>
> > free tools in the system?
>
> Because it can't.
>
> Regards
> Ansgar Wiechers
> --
> "Those who would give up liberty for a little temporary safety deserve
> neither liberty nor safety, and will lose both."
> --Benjamin Franklin
-- 
Nick Owen
WiKID Systems, Inc.
404.962.8983 (desk)
404.542.9453 (cell)
http://www.wikidsystems.com
At last, two-factor authentication, without the hassle factor