A major global cyber attack on Tuesday disrupted computers at Russia's biggest oil company, Ukrainian banks and multinational firms with a virus similar to the ransomware that last month infected more than 300,000 computers.
The rapidly spreading cyberextortion campaign underscored growing concerns that businesses have failed to secure their networks from increasingly aggressive hackers, who have shown they are capable of shutting down critical infrastructure and crippling corporate and government networks.
It included code known as Eternal Blue, which cybersecurity experts widely believe was stolen from the U.S. National Security Agency (NSA) and was also used in last month's ransomware attack, named WannaCry.
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