The sudden fall of a ransomware supplier once described as the world's most harmful cybercrime group has raised questions about Moscow's role in its development and the fate of its founder.

British clothes-to-food retailer Marks and Spencer on Wednesday said a cyberattack disrupting its online service is set to last through to July and hit group profit by around £300 million ($404 million).

New regulations threaten the security of the personal data of cryptocurrency users and may expose them to "physical danger", the platform at the centre of last week's Paris kidnapping attempt has claimed.

Coinbase on Thursday said criminals bribed and duped their way to stealing cryptocurrency from its users, then tried to blackmail the exchange to keep the crime quiet.

British retailer Marks & Spencer said on Tuesday that some personal data of its customers was stolen in a cyberattack that has crippled its online services for weeks. 

A US jury on Tuesday handed WhatsApp a major victory in its cyberespionage suit against NSO Group, ordering the Israel-based firm to pay some $168 million in damages.

South Korea's largest carrier SK Telecom started on Monday to replace mobile SIM chips for its 23 million users following a data breach, prompting alarmed customers to form long queues for the replacements.

Chinese security officials said Tuesday they had implicated three US "secret agents" in cyberattacks during February's Asian Winter Games in the northeastern city of Harbin, offering a reward for information on the alleged spies.