author of the machine or a moderator/admin configures a background process or a scheduled task which restores the credentials of the service as they should be.
For NetMon I did put something in place when testing the machine. Every 42 minutes NetMon is restored back to a normal condition (was for other things, not password). I wanted it to be quicker but it also logs all users out of the box when it does this. I could probably look into creating a scheduled task to just change the password but wasn’t a super trivial thing to do with how the application is installed.
I have looked at free a few times throughout the day, and haven’t really seen many people changing the credentials. It is ungodly slow or broken at times due to brute forces.