Re: Oodles of 529 Logon Failures every 2:00 AM

From: Roger Abell (mvpNOSpam_at_asu.edu)
Date: 08/28/04

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    Date: Fri, 27 Aug 2004 23:43:42 -0700
    
    

    Wow, that is a massively confused situation (and large but
    mostly reasonable x-post I leave untouched)

    I am inlining some comments that may shed some light, and
    hope (for your sake) that others add more.

    -- 
    Roger Abell
    Microsoft MVP (Windows Server System: Security)
    MCSE (W2k3,W2k,Nt4)  MCDBA
    "-" <-@-.com> wrote in message news:eJybcSIjEHA.3664@TK2MSFTNGP12.phx.gbl...
    > Hello,
    >
    > My Windows 2000 domain is getting an error every night at 2AM because it
    > can't lock out the Administrator account.
    So you are saying that the domainname\administrator account
    is being (or rather the attempt is made to have it) locked out.
    > Yes, exactly; "why is it being
    > told to lock out in the first place?"
    because the invalid login count threshold is reached within
    the time allowed, as you well know
    > I don't think we're under attack
    > because it is every night at the same time and because I have found some
    > information which may shed some light on it.
    >
    Gut level feeling are often right, but sometimes wrong.
    Why do you not think it an attack?
    > It seems that at 2:00 AM some process happens that all of the local
    > administrator accounts on the servers get a failed login to their local
    > machine.
    So, the process is attempting to log in with the domainname\administrator
    and with each machine\administrator account
    > The domain registers these logon failures I suppose because the
    > machine itself is a member of the domain.
    No.  The login attempts are logged where authentication is processed.
    For machine\administrator this is on machine, for domain\administrator
    this is on a domain controller
    > The really weird thing is that
    > the "logon type" shows as type 3, network.
    ??
    > How can a local account have a
    > network logon to its own machine?
    >
    Nothing strange here.  If login is by use of a network based
    access.  First, it sounds like at each machine, the process may
    be attempting to use in turn machine\admininstrator and also
    domain\administrator.  This likely originates on some machine
    other than the one targetted, but it could orginate there and still
    be login type 3.
    > More wierdness, wherever the local admin account of the server has been
    > changed, _that_ name shows up with the failed 529.
    This indicates that either you have not tightened the machines (and if the
    domain\administrator account falls into this camp, tightened the domain)
    so that it does not allow enumeration of accounts; or, that the process that
    is behind the behavior has access to a valid login so that it can enumerate
    account names non-anonymously.  If you can query against the SAM of
    account info, it is not hard to know which are admins.
    > The domain name is
    > _always_ the name of the local server, the AD domain is not referenced
    even
    > once in all 200 of the 529's.
    >
    I do not follow what that said, as it seems to say one thing and then
    say that it is not what was just said.
    > Something... is causing these failed local admin logins to happen every
    > night at 2AM on servers.
    Yes.  As they say on Mission Impossible, your task, should you choose
    to accept it, is . . .
    > I think that's why the domain admin account is
    > receiving a call to get locked out is; because the domain is confusing the
    > local admin accounts with the domain admin account, and thinking that _it_
    > is the culprit.
    Again, I got lost on what that was saying.  "The domain admin account
    is receiving a call to get locked out is . . ."  ??
    >
    > The first thing we're going to do is rename the domain admin account (yes
    I
    > know I should have done this a long time ago, but there are services,
    > scheduled tasks, etc. running under that name that I have to track down
    and
    > remediate before I change it).
    >
    Not just the domain\administrator account, but each machine\administrator
    account (and, ideally not all to the same thing).
    Reset passwords while at it.
    > The next thing I will do is I will check with our server team about
    nightly
    > processes/tasks that may be occurring at 2AM,
    Excellent idea, especially now that it is apparent that there are
    evidently admins of servers in your environment doing things
    of which you may have no awareness.
    Also, you may want to consider reviewing successful logins
    onto domain accounts, or onto the servers, at about the same
    time, or in the interval before the event begins.
    Do you have uplevel machines ?  The event logs on uplevels
    will provide info on the originating IP for the failed attempts.
    > but I wonder if there is
    > something in the undulations of AD itself that is triggering this,
    no, not that I can thing of, but it certainly could be programmed
    to do so, just not "as shipped"
    > such as a
    > master browser election.
    >
    That is pre-AD, and is non-authenticated.
    My first thought is dumb backup software someone is trying out
    and did not configure, or something like Nessus that someone has
    decided would be good to turn loose at 2 am to scan about.
    > If anyone can shed any light or has experienced something similar, I am
    open
    > to any advice you could give.
    >
    > Thanks a bunch!!
    >
    Good luck.  Collect the dominoes and the picture will point
    your nose in the right direction.
    -- 
    Roger
    

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