Malware extortion virus attacks on rise "There are enormous numbers of people being hit by the malware": James Kavanagh. Photo: Ellie-Marie Watts It has a name like a B-grade horror film and computer experts say the latest virus attacking Australian computers is one of the most vicious they have ever seen. The number of attacks by the insidious "cryptolocker" has jumped in the past few weeks, according to James Kavanagh, Microsoft's chief security adviser in Australia, who warns it is one of the nastiest viruses he has encountered. After infecting a computer the virus "ransoms" the user to regain control of their machine. "There are enormous numbers of people being hit by the malware," Mr Kavanagh said. It usually turns up as an attachment to an email and if you run it, it grabs documents, images etc and encrypts them and to get them back you have to pay in a virtual currency. He recommended that users backed up and retained all their files because even if they managed to remove the virus from their computer, they may not be able to recover all their files. Tens of thousands of Australians are hit by malicious software programs every day that infect computers and either lock up them and refuse to release them until they pay up thousands of dollars or steal their information. On Friday, the Australian Communications and Media Authority reported that almost 60,000 incidents had occurred in which malicious software had been detected. Bruce Matthews, the manager, e-Security Operations at ACMA said there were many types of scam and ransomware but they had one thing in common. "It is a criminal activity which is very similar to extortion," Mr Matthews said. The malware enables the computer to be controlled remotely for illegal activities including sending out spam, hosting phishing sites and performing denial of service attacks on internet infrastructure.