Ransomware cyber attack strikes world's biggest firms
A ransomware cyber attack has struck some of the world's biggest companies, the National Cyber Security Centre has confirmed.
Major firms in the UK, US, Russia, France and Germany were among those to be left in chaos as a result of the new 'Petya' attack.
It appears to have largely begun in Ukraine before spreading throughout the world.
There is very little information about who might be behind the attack, which appears to be similar to the WannaCry hack which paralysed NHS systems across the UK last month.
The National Cyber Security Centre, which is part of GCHQ, said: "We are aware of a global ransomware incident and are monitoring the situation closely.
"The NCSC website provides advice to the public and business on how to protect your digital systems."
In Ukraine, Prime Minister said the attack was "unprecedented".
Officials reported serious intrusions at the Ukrainian national power grid, banks and government offices, where one senior official posted a photo of a darkened computer screen and the words, "the whole network is down."
International advertising giant WPP said a number of its companies have been affected and it is currently "assessing the situation".
Global law firm DLA Piper, which has offices in London and other parts of the UK, and Dutch-based delivery company TNT Express, were also caught up in the attack.
Other major firms to be attacked include Russia's Rosneft energy company, US pharmaceutical company Merck, and shipping company AP Moller-Maersk.
Those whose computers were hacked are met with a message saying "Oops, your important files are encrypted".
"Perhaps you are looking for a way to recover your files, but don’t waste your time," it continues.
"Nobody can recover your files without our decryption service."
It says that the user can only restore their computer and get back their document by paying $300 dollars in the crypto-currency bitcoin.
However, experts have warned in previous similar hacking attacks that paying the ransom does not always guarantee that the computer and its files are then restored.
Marco Cova, senior security researcher at malware protection company Lastline, said the latest Petya attach appeared to be similar to the WannaCry ransomeware that caused disruption a new weeks ago.
"This attack also shows that criminal groups are always ready to copy and improve on one another's techniques once they see that something is effective," he said.
Mr Cova added that the serious real world consequences of the attack "points once more at the fragility of our current infrastructure that can be substantially affected by what appears to be a "traditional", widespread and non-targeted attack.”