BugTraq
NTLM HTTP Authentication is insecure by design - a new writeup by Amit Klein Jul 18 2005 05:40PM
Amit Klein (AKsecurity) (aksecurity hotpop com) (1 replies)
Re: NTLM HTTP Authentication is insecure by design - a new writeup by Amit Klein Jul 19 2005 09:35AM
3APA3A (3APA3A SECURITY NNOV RU)
Dear Amit Klein (AKsecurity),

--Monday, July 18, 2005, 9:40:32 PM, you wrote to bugtraq (at) securityfocus (dot) com [email concealed]:

AKA> NTLM HTTP Authentication
AKA> (and possibly other connection-oriented
AKA> HTTP authentication and authorization protocols)
AKA> is insecure by design

NTLM authentication is insecure by design for external authentication,
because of "single signon" ideology. NTLM authentication can be used
for NTLM proxy attack. For example, attacker who can hijack or spoof
server connection with NTLM authentication can use this connection to
access different Web server, mail server or file server with client's
credentials. This is known for many years and was discussed for many
times. Few years ago Internet Explorer was patched to use NTLM
authentication only for local network zone. Local network are hosts
with NetBIOS name (for example WEBSRV, excluded by default from proxy)
and list of proxy exclusions.

So, under default configuration, NTLM will not be used through proxy
server, at least in Internet Explorer.

--
~/ZARAZA
http://www.security.nnov.ru/

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