RE: [Full-Disclosure] RE: Unchecked buffer in mstask.dll

["Polazzo Justin" <Justin.Polazzo@xxxxxxxxxxxxxxxxxxxxx>]

> (Hmmmm -- does it also fail on
W2K3??)

>I had to specifically click on the "Program" tab, which evoked a null-
>pointer read attempt
 
It works on 2k3, same steps taken.
 
jp

        -----Original Message----- 
        From: Nick FitzGerald [mailto:nick@xxxxxxxxxxxxxxxxxxx] 
        Sent: Wed 7/14/2004 11:03 PM 
        To: bugtraq@xxxxxxxxxxxxxxxxx; full-disclosure@xxxxxxxxxxxxxxxx 
        Cc: 
        Subject: Re: [Full-Disclosure] RE: Unchecked buffer in mstask.dll
        
        

        "Jordan Cole (stilist)" <stilist@xxxxxxxxx> to Paul Szabo:
        
        > > Being curious, on Win2k, I copied cmd.exe (from winnt\system32) as 
xyz.pif;
        > > then (right-click) Properties, Program crashes explorer.
        
        I had to specifically click on the "Program" tab, which evoked a null-
        pointer read attempt (at a guess, something in the .PIF parser assumes
        a length or offset will always be >0 so doesn't do any sanity checking,
        and/or some higher level routines don't do any checking).
        
        > I'd say that's because you changed the filetype; pif files simply
        > contain information on how to handle a DOS executable; they aren't a
        > program themselves. All you did was make it get confused and kill
        > itself.
        
        Yeah, but how long is it now since we've been telling programmers
        "don't trust user-supplied data"??  (Hmmmm -- does it also fail on
        W2K3??)
        
        And don't you also find the inconsistencies this throws up at least
        somewhat interesting?
        
        Rename a PE executable to a .PIF extension, right click, ask to see the
        file's properties and splat -- whatever code is invoked to handle that
        task dies a stupid, if not ugly, death because internally the file is
        the wrong type.  However, if you double-click that renamed file it is 
        executed as if nothing is amiss.
        
        And to think that some folk will see this as further reason to enforce
        their belief that when it comes to security and code quality, Microsoft
        really just doesn't get it...
        
        Why did MS make ".EXE files renamed as .PIF" execute "properly"?  Aside
        from "because we can", I'd not be at all surprised if it was on some
        internal "stupid user tricks we should eliminate support calls for"
        list.  But, whatever the reason, did anyone at Microsoft give two
        milliseconds of thought to the security (or other) consequences of that
        design decision?  I seriously doubt it and I'm sure I'm far from alone
        in that...
        
        
        --
        Nick FitzGerald
        Computer Virus Consulting Ltd.
        Ph/FAX: +64 3 3529854
        
        

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