5 April 2012
Half a million Mac computers 'infected with malware'
Apple laptop computer Dr Web says most infected computers are in the US
More than half a million Apple computers have been infected with the
Flashback Trojan, according to a Russian anti-virus firm.
Its report claims that about 600,000 Macs have installed the malware -
potentially allowing them to be hijacked and used as a "botnet".
The firm, Dr Web, says that more than half that number are based in the
Apple has released a security update, but users who have not installed
the patch remain exposed.
Flashback was first detected last September when anti-virus researchers
flagged up software masquerading itself as a Flash Player update. Once
downloaded it deactivated some of the computer's security software.
Later versions of the malware exploited weaknesses in the Java
programming language to allow the code to be installed from bogus sites
without the user's permission.
Dr Web said that once the Trojan was installed it sent a message to the
intruder's control server with a unique ID to identify the infected
"By introducing the code criminals are potentially able to control the
machine," the firm's chief executive Boris Sharov told the BBC.
"We stress the word potential as we have never seen any malicious
activity since we hijacked the botnet to take it out of criminals'
hands. However, we know people create viruses to get money.
"The largest amounts of bots - based on the IP addresses we identified -
are in the US, Canada, UK and Australia, so it appears to have targeted
Dr Web also notes that 274 of the infected computers it detected
appeared to be located in Cupertino, California - home to Apple's
Java's developer, Oracle, issued a fix to the vulnerability on 14
February, but this did not work on Macintoshes as Apple manages Java
updates to its computers.
Apple released its own "security update" on Wednesday - more than eight
weeks later. It can be triggered by clicking on the software update icon
in the computer's system preferences panel.
The security firm F-Secure has also posted detailed instructions about
how to confirm if a machine is infected and how to remove the Trojan.
Although Apple's system software limits the actions its computers can
take without requesting their users' permission, some security analysts
suggest this latest incident highlights the fact that the machines are
"People used to say that Apple computers, unlike Windows PCs, can't ever
be infected - but it's a myth," said Timur Tsoriev, an analyst at
Apple could not provide a statement at this time.