OSEC

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Re: Authentication flaw in microsoft SMB protocol

From: Dave Aitel (daveimmunitysec.com)
Date: Sat Apr 19 2003 - 11:11:33 CDT


Also found and demonstrated by dildog at defcon 3 years ago. So don't
hold your breath waiting for that patch.

Dave Aitel
Immunity, Inc.
http://www.immunitysec.com/

On 19 Apr 2003 13:24:33 -0000
<seclabce.aut.ac.ir> wrote:

>
>
> Detailed information:
> http://seclab.ce.aut.ac.ir/vreport.htm
>
> Summary
> =======
> Microsoft uses SMB Protocol for “File and Printer sharing service” in
> all versions of Windows. Upon accessing a network resource, NTLM
> Authentication is used to authenticate the client on the server. When
> a logged-in user requests for a network share on the server, Windows
> automatically sends the encrypted hashed password of the logged-in
> username to the target SMB server before prompting for password.
> Although the hashed password is not sent in plaintext format, and it
> is encrypted by the server challenge, a malicious SMB Server could use
> this information to authenticate on the client machine and in many
> cases, gain full control over the shared objects of the client such as
> C$, etc.
>
...
> Exploit
> =======
> We will publish the exploit code after a patch be created by software
> vendor.