Celebrity data leaked after ransomware attack on London's Graff jewellers

London-based diamond specialist Graff has reportedly been hit by a ransomware attack, prompting an investigation from the Information Commissioner's Office (ICO).

The attack is believed to have been carried out by Conti, an infamous Russia-based ransomware group that has also been blamed for a recent uptick in attacks across the US.

A total of 69,000 documents have been leaked on the dark web already, a number which represents just 1% of the total files Conti has stolen, the hacking group claimed. The list of victims includes high-profile names such as ex-footballers David Beckham and Frank Lampard, former president Donald Trump, actors Tom Hanks and Samuel L Jackson, and disgraced businessman Sir Philip Green, according to the Mail on Sunday, which first reported the story.

“We have received a report from Graff Diamonds Limited regarding a ransomware attack," said the ICO, in an email to IT Pro. "We will be contacting the organisation to make further enquiries in relation to the information that has been provided."

It's believed 11,000 of the company's customers may be affected, 600 of which are UK nationals, according to the Mail on Sunday. Information such as client lists, invoices, receipts, and credit notes were included in the hack.

In some cases, customer names and addresses used for billing and shipping were included, and in other cases details of what the customer bought - and the cost of said items - were leaked online.

Conti is believed to be demanding a sum in the tens of millions in order to prevent the further release of customer information, however Graff has said it has been able to rebuild and restart its systems with no permanent loss of customer data.

"Regrettably we, in common with a number of other businesses, have recently been the target of a sophisticated – though limited – cyber attack by professional and determined criminals," said Graff in a statement. 'We were alerted to their intrusive activity by our security systems, allowing us to react swiftly and shut down our network. We notified, and have been working with, the relevant law enforcement agencies and the ICO.

'We have informed those individuals whose personal data was affected and have advised them on the appropriate steps to take."

Conti's recent surge in activity prompted the US' CISA, FBI, and NSA to release a joint advisory to US and international businesses alerting them to the group's most common attack methods.

These include spearphishing campaigns, exploiting stolen or weak remote desktop protocol (RDP) credentials, fake software promoted though web adverts, and common vulnerabilities in external assets.

The attack follows a string of major raids on international businesses attributed to Conti. Nokia subsidiary SAC Wireless said it had become victim to a Conti ransomware attack in June, while 16 US healthcare and first responder organisations were also targeted just one month prior.