Wow, reading this, sounds like the script of some Japanese horror movie. Sadly enough, it's entirely true - a recent hacking incident has scourged the entirety of the ARMA 3 Alpha community, spreading like wildfire through the servers and leaving most of the multiplayer and even the single player maps barren wastelands (not literally, though that would have been an awesome virus). It seems to have originated from a server which got hacked by a player with no ID, where apparently a file injection occurred, followed by a new message that was displayed upon joining the server, reading:

"Thank you BIS for making my hacking life so much easier. This BIS_fnc_MP command is just what i need to screw people up. Why don't you go bitch on the forums about it? Hmmm...it's not exactly hacking anymore, now that it's a feature..."

Real mature. Anyway, the situation escalated quickly, ultimately ending up with servers all over, and even single player , being heavily affected. There's been an uproar in the forums, with people clamouring for Bohemia Interactive to take action, and angry rants about their failure to include security in the game, despite its Alpha tag. How bad has it become? As to quote forum user Forty40:

"In the moment I’m typing there's 463 servers online, 400 of them are completely empty and there's only 289 users playing online (MP). Right, it's alpha, there's no security.. so, since there's no security we must accept this situation and let this alpha-with-no-security dying, waiting for someone to come up with this awaited "security".

Now, honestly, there's no other solution than moving to another game now?"

Still, Bohemia Interactive has remained one of the few companies that truly look after its gamers, and thus I appeal to all for patience. I fully trust that they are on the situation and currently working their hardest for a viable solution.