Re: NULL sessions on Windows 2000 systems [Was: Re: [Full-disclosure] Re:It's not that simple...]

From: yossarian (yossarian_at_planet.nl)
Date: 08/18/05

  • Next message: Valdis.Kletnieks_at_vt.edu: "Re: [Full-disclosure] Sub_level attaq!"
    Date: Thu, 18 Aug 2005 15:59:45 +0200
    To: Jean-Baptiste Marchand <jbm.lists@gmail.com>, full-disclosure@lists.grok.org.uk
    
    

    You imply with 'hard-coded' that removing them from the registry does not
    help. This is new to me? Can you plz. elaborate?
    ----- Original Message -----
    From: "Jean-Baptiste Marchand" <jbm.lists@gmail.com>
    To: <full-disclosure@lists.grok.org.uk>
    Sent: Thursday, August 18, 2005 9:58 AM
    Subject: NULL sessions on Windows 2000 systems [Was: Re: [Full-disclosure]
    Re:It's not that simple...]

    >* yossarian <yossarian@planet.nl>:
    >
    >> In the original X-Force paper named pipes were mentioned besides Null
    >> Sessions. Does it need both or either one - the paper isn't clear on
    >> this?
    >> The named pipes seem to have dropped from all discussion.... Anyway,
    >> never
    >> broke anything by disabling them, either. This is a registry hack
    >> described
    >> in the MS Hardening guides for 2000 and 2003 server. Just like Null
    >> sessions. Elsewhere dunno, but probably, never bothered.
    >
    > A NULL session usually refers to an anonymous connection to the IPC$
    > share, giving remote access to named pipes.
    >
    > Some named pipes can be opened anonymously (these named pipes appear in
    > the NullSessionPipes registry value), i.e. in the context of a NULL
    > session.
    >
    > In addition, 6 named pipes are harcoded in Windows 2000 and can always
    > be opened anonymously:
    >
    > http://www.hsc.fr/ressources/presentations/null_sessions/img7.html
    >
    > The recent PnP vulnerability (MS05-039) can be anonymously exploited on
    > Windows 2000 systems with 139/tcp or 445/tcp open, *except* if the
    > RestrictAnonymous registry value is set to 2.
    >
    > This is because the only way to disable NULL sessions *entirely* on
    > Windows 2000 is to set RestrictAnonymous to 2:
    >
    > http://www.hsc.fr/ressources/presentations/null_sessions/img23.html
    >
    > Please read my recent presentation about NULL sessions, many people seem
    > to know about NULL sessions but fewer people really understand the
    > technical details:
    >
    > http://www.hsc.fr/ressources/presentations/null_sessions/
    >
    >
    > --
    > Jean-Baptiste Marchand
    > _______________________________________________
    > Full-Disclosure - We believe in it.
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