Ukraine bore the brunt of the June attack, in which the ‘Petya’ worm spread among corporate computer networks
LONDON—British officials blamed Russia for last June’s massive “Petya” cyberattack, which crippled computer networks at multinational firms including FedEx Corp., container-ship giant A.P. Moeller-Maersk A/S and pharmaceutical firm Merck & Co.
Ukraine, which bore the brunt of the attack, accused Russia at the time of orchestrating the attack. Wednesday’s allegations by London represented the first time a major Western government has pinned blame on Moscow for the incident.