So, I took one step back and take a look at the records. So far, I notice the passwords had been changed recently and whoever did left the company would not have access to it. So that rules angry ex-employee out.
The VPN was a connection to another site across the globe. The sole purpose was for replication only. And by that, nobody will log in to the server. The channel was also encrypted. So, unless the machine on the other site was infected, its highly unlikely something could had came in through the VPN. And moreover, the VPN is only on one of the machine, not the other. The 2 machines were on seperate network which could not reach one another either. So not possible to infect via the network. Thumbdrive, maybe, but that's restricted only to some of the staff and highly unlikely anyone was there on Sat and Sun where the first server rabbit went down. So, this is out too.
I am almost at my witts end. Then I had to go around and drink coffee with the rest of the staff to find out what they had been doing, any progress etc. One thing caught my mind. They were in progress of hardening the server based on Microsoft Best Practice. Well, at least they started to.
Giving there were no other choices, I feel this is one possibility that could had went wrong. So, I had the staff show me what was performed. One of them was undoubtly the auditing, which we can safely ruled out as an attacker's trick to clear the log. Then there was also some tweaks so restrict the user's access to the event viewers and some other services. I probably did not need to know the details, but the mention about services has brighten my way a bit.
I went back to the rabbit servers and check if the services were up. My hunch was right. There were barely any services running. I tried to manually start some of the services but were met with a permission error. I run some quick check on the internet and found more than 10 ways to solve it, but none of them worked. At this point of time, the staff has already begin to repair server rabbit 2003 by a in place reinstall of the files using one of the cloned drives.
I knew my time is running short and I had to quickly nail the problem. Looking at the services tab which has a block of GUI error, I suddenly saw one critical service was not up. I knew I had hit the jackpot. This was where the problem began....