Troubleshooting With Near Zero Access

Early one morning last week I attempted to RDP into my lab to test something out I was looking into at work. Access to my terminal server was fine, but from there, I was unable to access any other system on my network. Every system that I attempted to RDP into came back stating that my user account was unauthorized for RDP access on that system. The user is a Domain Admin so there should be no reason for that. Not too long after, I noticed that the terminal server was asking for a username and password for everything with is out of character for my user account. And after accounting, I get access denied errors for anything requiring elevated privileges. My first thought was that my network was compromised.