Re: Writing to Windows Security Log

From: Adrien de Beaupre (adrien.debeaupreat_private)
Date: Fri Dec 07 2001 - 13:35:22 PST

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    While not exactly what you are looking for this tool can selectively remove
    entries
    from the NT/2K event log. Does not work remotely and requires admin access.
    
    http://www.ntsecurity.nu/toolbox/winzapper/
    
    From his FAQ:
    Q: Is it possible to add your own "made up" event records to the log?
    A: Yes, that's possible, but I haven't added that feature becuause I think
    it's too nasty. ;-)
    You could insert completely "made up" records anywhere in the log.
    
    Adrien
    
    ----- Original Message -----
    From: "Tina Bird" <tbird@precision-guesswork.com>
    To: "Mr Rufus Faloofus" <foofusat_private>
    Cc: <pen-testat_private>; <jon.bullat_private>;
    <marvin.marinat_private>; <tbird@precision-guesswork.com>
    Sent: Wednesday, December 05, 2001 4:16 PM
    Subject: Re: Writing to Windows Security Log
    
    
    > Let me provide more details.
    >
    > We all understand that one of the big problems with
    > UNIX syslog-the-network-protocol is that it's UDP -
    > not authenticated, not reliable.  An evildoer who
    > wants to make my logs less trustworthy can easily
    > send bogus data to my central loghost, at a minimum
    > introducing nonsense into my audit stream, and at
    > a maximum, knocking the loghost off line.
    >
    > As explained below, a Windows application or service
    > that registers itself with the Event Log service can
    > write messages to the Windows System and Application
    > Logs.  So one way for me to introduce a roughly
    > equivalent source of bogus data into an Event Log stream
    > is to register an illegitimate application with
    > associated DLL with the Event Log service.  I expect
    > that's a relatively straightforward thing to do, given
    > how easy it is to install back doors on Windows boxes --
    > although one doesn't typically write back doors with lots
    > of logging capabilities, it might make sense to create
    > a program that muddied up the logs.
    >
    > However, the only things on a Windows box that can write
    > to the >Security< Event Log are the LSA and the Event
    > Log service itself, which have the SeAuditPrivilege.
    > This suggests that the Security Event Log has a much
    > higher level of assurance than anything in the off-the-shelf
    > UNIX world.
    >
    > This conclusion startled me ;-) so I figured I'd ask this
    > group if anyone knew of a tool that would get around
    > this access restriction.  Does that clarify what I'm
    > after?
    >
    > thanks -- tbird
    >
    > On Wed, 5 Dec 2001, Mr Rufus Faloofus wrote:
    >
    > > At 07:26 PM 12/4/01 -0600, Tina Bird wrote:
    > > >Anyone out there have a tool that allows me to
    > > >forge Windows Security Event Log data?
    > >
    > > Depends what you mean by "forge," and what kind of access
    > > you have to the machine.  To log an event, the Right Way is
    > > to register a DLL with your messages in it.  It's not hard
    > > (see LOGEVENT.EXE from the resource kit, or section 15.2 in
    > > Marshall Brain's Win32 SYSTEM SERVICES: The Heart of Windows
    > > 95 and Windows NT [Prentice Hall PTR: NJ]: 1996), and you
    > > can roll your own.
    > >
    > > But these don't "forge" events, in the sense that the
    > > events they record are legitimate messages, and don't appear
    > > to come from bogus sources.  So, for example, if you want
    > > to insert an apparent IIS message into a log (not using
    > > IIS), this would be hard.  Also, we're assuming, so far,
    > > that you have NetBIOS access to the machine in question.
    > >
    > > If you want to insert arbitrary false messages into the
    > > files, that's complicated: the logging API doesn't permit
    > > it, and you'd be relegated (I think) to either finding a
    > > flaw in it-- like the recent discussions involving URLs
    > > with special characters embedded in them (but related to
    > > the security log, instead of the application log), or to
    > > programmatically editing the log files (which also is
    > > tricky, I bet).
    > >
    > > Does this help at all?
    > >
    > > --Foofus.
    > >
    > >
    >
    >
    >
    >
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