Apple Devices Hit By Hack Demanding 'Ransom'
Some Apple users have had their devices locked by hackers demanding payment before releasing them, according to messages on the company's online forum.
The majority of those affected appear to be in Australia and New Zealand.
One user, veritylikestea, wrote on the company's support board that her iPad had "suddenly locked itself".
She wrote: "I went to check my phone and there was a message on the screen (it's still there) saying that my device(s) had been hacked by 'Oleg Pliss' and he/she/they demanded $100 USD/EUR (sent by paypal to lock404(at)hotmail.com) to return them to me."
Pmckiernan wrote: "The lock screen appeared and at the same time I received two emails from apple saying lost mode had been activated and one showing me the location of the iPad.
"Luckily I had a pass code set so was able to regain control immediately. All very strange."
It is unclear how the devices have been compromised, but Stay Smart Online, an Australian government website, is advising users to change their Apple ID passwords "as soon as possible" and not to pay the ransom.
"Reports by affected users suggest that this attack is possibly the result of hackers compromising the device owner's Apple ID and using this to access their iCloud account," a message on its website said.
"From their iCloud account a hacker can activate the device's 'Lost Mode', and possibly reset the phone's access code.
"It is not confirmed if or how these Apple IDs and passwords were accessed, but suggestions include that hackers may be simply reusing information they may have discovered during a breach of other online services."
Sky News has approached Apple for comment.