Mysterious "Support" account created on Win2k server

["Ostfeld, Thomas" <tostfeld () kimpact com>]

One of my web servers appears to have had an intrusion.  The box is Win2k
Advanced Server, SP3, up to date on all security patches.  I first became
aware of a problem when the main website hosted on the box became
inaccessible.  Checking the machine, I discovered that the Local Security
Policy had been altered as to remove the Everyone and Local Administrators
group from "Access this machine from the network" policy  In place was a
single local account called "Support" that I did not recognize.

Looking into the accounts database, I discovered this account with a
description of "Built in account for providing user support."  It was also
part of the administrators group.  Needless to say, this looked suspicious,
so I locked the server back down and set up intrusion detection to look for
further attempts to exploit the account.

I know approximately when the attack occurred, but I am still puzzled as to
how it was done.  The web logs show the usual IIS root exploit attempts, but
those all fail.  Everything else looks normal.  I've scoured the machine
pretty thoroughly for bots, trojans, viruses, hidden and altered files, and
have so far come up empty.  No weird open ports either.

Has anyone seen this before?  There is one or two postings of the same
nature on Google, but little else to give me something to go on.

Tom Ostfeld
Knowledge Impact
Ostfeld7 (AIM)


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