"We've got all the antivirus stuff in place - there's no sign of a virus. They literally got in, hijacked the server and then ran their encryption software," he said.
People often think that an AV will protect them from hackers.
Hackers rely on skills, network tools and social engineering to penetrate a system
Users can rely only on Hardware/Softwares firewalls, Honeypot and caution measures to oppose them
AVs protect vs malwares not from hackers that penetrate the system and use encryption softs (in that case).
btw, i wonder what was their security stuff...McAffee?