I'm surprised that a regular user can write to that field.
If you are looking for stale computer accounts, the machine account password age is a pretty good indicator. I just bring up a list of computers in Hyena and sort on the password age column. In the old days, I was doing it using the MachAcctPWAge utility written by Howard Bullock. In fact when we did our NT to AD migration, we used it and/or Hyena to ferret out thousands of stale accounts.
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Give a man a fish and he will be back for more. Slap him with a fish and he will go away forever.
