“Double-Tap” reset of the krbtgt account

We recently ran a “double-tap” reset of the krbtgt account in our Active Directory and ran into very few problems. We have the default 10 hour Kerberos ticket lifetime configured.

EDIT: The biggest issue was an internal .NET Portal that was federated with ADFS, it needed to be restarted

We ran the script that is out on Microsoft’s github repository.

We ran this first in our test environment and then scheduled the run for our Production environment a week night evening at 10pm to make sure people would be around if there were issues the following morning.

The recommended way to run this script is using the following modes:

  1. Mode 1 – Informational Run Only
  2. Mode 8 – Create bogus krbtgt test account
  3. Mode 2 – Simulation Run to verify replication
  4. Mode 3 – Simuation Run to verify replication and password reset of bogus krbtgt
  5. Mode 4 – Real Run, Modifying Real krbtgt Account
  6. Mode 9 – Cleanup bogus krbtgt test account

We ran Mode 3 and Mode 4 twice, on the second run of Mode 4 you will see some warning text that there could be a major domain impact.

The only major impact that was noticed in our environment was that remote desktop to many of our servers stopped working if using the fully qualified name. A workaround to this would be to use the IP which will use NTLM authentication.

However, after our 10 hour ticket time all machines were back to working as expected.

This script should be run a couple times a year depending on who you ask for only a single-tap reset of the account. I’ve heard recommendations from every 90 days to every 180 days. It should also be run anytime someone who can forge golden tickets leaves the environment (Twice if there is concern).