RE: White paper: Exploiting the Win32 API.

From: John Howie (JHowieat_private)
Date: Tue Aug 06 2002 - 10:44:17 PDT

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    Chris,
    
    This class of attack is not new, it has been discussed before. While you
    can assert that the blame lies with Microsoft (and I'll admit they do
    have some responsibility to address the problem you describe) the chief
    blame lies with the vendor of the software whose bad programming you are
    exploiting. There is no excuse to put a window for a process with the
    LocalSystem security context on a user's desktop. I am not aware of any
    Microsoft application that makes such a mistake.
    
    John Howie
    
    
    -----Original Message-----
    From: Chris Paget [mailto:ivegottaat_private] 
    Sent: Tuesday, August 06, 2002 9:14 AM
    To: bugtraqat_private
    Subject: White paper: Exploiting the Win32 API.
    
    
    I have written a white paper documenting what I believe is the first
    public example of a new class of attacks against the Win32 API.  This
    particular attack exploits major design flaws in the Win32 API in
    order for a local user to escalate their privileges, either from the
    console of a system or on a Terminal Services link.  The paper is
    available at http://security.tombom.co.uk/shatter.html
    
    In order to pre-empt some of the inevitable storm about responsible
    disclosure, let me point out the following.
    
    1)  The Win32 API has been in existence since the days of Windows
    NT3.1, back in July 1993.  These vulnerabilities have been present
    since then.
    
    2)  Microsoft have known about these vulnerabilities for some time.
    This research was sparked by comments by Jim Allchin talking under
    oath at the Microsoft / DoJ trial some 3 months ago.
    http://www.eweek.com/article2/0,3959,5264,00.asp  Given the age of the
    Win32 API, I would be highly surprised if they have not known about
    these attacks for considerably longer.
    
    3)  Microsoft cannot fix these vulnerabilities.  These are inherent
    flaws in the design and operation of the Win32 API.  This is not a bug
    that can be fixed with a patch.
    
    4)  The white paper documents one example of these class of flaws.
    They have been discussed before on Bugtraq, however to my knowledge
    there have been no public working exploits.  I have just documented
    one way to get this thing working.
    
    5)  This is not a bug.  This is a new class of vulnerabilities, like a
    buffer overflow attack or a format string attack.  As such, there is
    no specific vendor to inform, since it affects every software maker
    who writes products for the Windows platform.  A co-ordinated release
    with every software vendor on the planet is impossible.
    
    Chris
    
    -- 
    Chris Paget
    ivegottaat_private
    



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