Security Basics mailing list archives
Re: sshd for windows
From: ktabic <lists () ktabic co uk>
Date: 22 Jun 2003 17:46:33 +0000
Thats totally true, but worthless. Authentication isn't the problem, it's the transmission that's in the clear, so now you're sending your loging name and password in cleartext. Sure, they're stored in NTLMv2 format at the other end, but what does that matter if they just put a sniffer on the wire?
NTLMv2 is not the storage meathod of passwords in Windows 2k/XP, thats what the SAM and the Active Directory do. NTLMv2 is a challenge/response authentification meathod. When connecting to a windows 2000 telnet server, from the windows 2000/XP telnet client, the authentification of the session is done via NTLMv2. It goes like this: Client: Opens TCP port to server and sends username Server: Sends a random string of bytes to the client (called the challenge) Client: Prompts user for password (or just uses the users password hash), hashes the password then uses the hash to encrypt the random string of bytes. This encrypted string is sent back to the server. It is called the Response Server: Decrypts the received encrypted sting of bytes, using the offical password hash that is stored on the server. Server: If the decrypted random string of bytes matches the original string of bytes that was sent to the client, the user is authentic. If not the password was wrong, and the rest of the connection is refused. At no point in the authentification, is the password itself sent in plain text, nor is it sent in an encrypted form. All the authentification is performed using hashes of the password as a key to encrypt a random string. The server itself doesn't need to know the users password, just the password hash, and that isn't sent from the the client machine, but is already stored on the server (or the ADS) ktabic -- Woot! --------------------------------------------------------------------------- Evaluating SSL VPNs' Consider NEOTERIS, chosen as leader by top analysts! The Gartner Group just put Neoteris in the top of its Magic Quadrant, while InStat has confirmed Neoteris as the leader in marketshare. Find out why, and see how you can get plug-n-play secure remote access in about an hour, with no client, server changes, or ongoing maintenance. Visit us at: http://www.neoteris.com/promos/sf-6-9.htm ----------------------------------------------------------------------------
Current thread:
- RE: sshd for windows, (continued)
- RE: sshd for windows DeGennaro, Gregory (Jun 18)
- RE: sshd for windows Depp, Dennis M. (Jun 18)
- Re: sshd for windows Bryan S. Sampsel (Jun 18)
- RE: sshd for windows Chris Berry (Jun 19)
- RE: sshd for windows DeGennaro, Gregory (Jun 19)
- RE: sshd for windows DeGennaro, Gregory (Jun 19)
- RE: sshd for windows wjnorth (Jun 20)
- RE: sshd for windows DeGennaro, Gregory (Jun 20)
- Re: sshd for windows Chris Berry (Jun 20)
- Re: sshd for windows Ansgar Wiechers (Jun 23)
- Re: sshd for windows ktabic (Jun 23)
- RE: sshd for windows Chris Berry (Jun 20)
- RE: sshd for windows Chris Berry (Jun 21)
- RE: sshd for windows DeGennaro, Gregory (Jun 21)
- RE: sshd for windows Chris Berry (Jun 21)
- RE: sshd for windows Depp, Dennis M. (Jun 21)
- RE: sshd for windows Depp, Dennis M. (Jun 21)
- Re: sshd for windows Chris Berry (Jun 24)