On a small network of machines (<1000) we have a user whose account is being locked out after an indeterminate interval following a password change.
We are having severe difficulties finding the source of the invalid logon attempts and I would appreciate it greatly if some of you could go through your thought process and the checks you would perform in order to fix the problem.
All I know for sure is that the account is locked out several (5+) times a day, I can't even be sure it's due to failed login attempts as there is no record of failure until the account is locked.
So far I have tried;
- Logging the account out of everything we can think of and back in with the new password
- Scanning the user's box for any non standard software which might perform an LDAP lookup
- Checking all installed services on our production boxes to check none are attempting to run under the account
- Changing the user back to their old password (Problem persists so perhaps password change is a red herring)
- Wireshark on a box where lots of LDAP authentication is performed - Rejects only occur after account is already locked out
- Clearing the credential cache in - Control Panel -> User Accounts -> Advanced
- Looking at the local
I'm at a loss for what to try. I am happy to try any suggestions you have in order to diagnose the issue. I think my question boils down to a simple request;
I need a technique for deriving the source (Application/Host) of the invalid login attempts which are causing the account to be locked.
I'm not sure if that's even possible but I suspect there must be more I can try.
EDIT - SOLVED
TLDR - RSS Feed Reader configured on Client Box with old credentials caused the Continuous Build Software (Which the reader tried to log into) to lock the account as it made a failed login attempt every 5 minutes.
I looked at the logs for the key pieces of infrastructure we have, grepping for the username in question. It was clear there were a lot of failed attempts for the Continuous Build Software. It was then a case of performing a wireshark capture between the two boxes to try and work out where the requests we coming from. We killed processes until we found the right one.
Thank you all for your help, it sounds so easy now it's sorted!