How the growing Russian ransomware threat is costing companies dear

As group members were led away in cuffs, FSB officers gathered crypto-wallets containing untold volumes of digital currency such as bitcoin. Others used money-counting machines to tot up dozens of stacks of hundred dollar bills.

The cybercriminals behind REvil had mastered a form of extortion orchestrated by seizing control of company computer systems and demanding payment to unlock them.

When the boss of a company such as KP gets the dreaded ransom note, no matter what time of day, their next call might well be to US cybersecurity firm Mandiant.

The importance of computer systems to company supply chains, he says, affords enormous power to any hackers who breach their defences.

Hackers, he says, will even hand-hold executives through the process of buying and transferring the cryptocurrency favoured for ransom payments.

Depending on the sophistication of the attack, the damage done by a prolonged shutdown, and whether the likes of Mandiant can fix it, there is sometimes little choice but to pay.

On top of operational disruption, firms risk regulatory fines if data is leaked, as well as huge damage to their reputations.