first, to answer your question: This is highly unlikely.
You can check your system's logs from right before the shutdown (or reboot for that matter), if you like, with this command:
This command shows the content of your logs and shows you five lines before the system reported that it would shut down now.
cat /var/log/messages | grep "runlevel: 0" -B 5
It should say somewhere in there, why the computer decided a reboot was necessary. You might want to use a larger value than 5
, if it just gives you the same stuff over and over.
I hope this gives you a clue as to what really happened,
Let me add a little something, which is of concern to me and many people in the free software community:
Your usage of the term "hacker" is somewhat inaccurate. Hackers are the good guys, who find security holes and report (not exploit) them. In fact, you stand a good chance of meeting some here on linuxquestions.
The correct term for this [insert not-nice term here] is "cracker".