A global cyberattack leveraging hacking tools widely believed by researchers to have been developed by the U.S. National Security Agency hit international shipper FedEx, disrupted Britain's health system and infected computers in nearly 100 countries on Friday.
Cyber extortionists tricked victims into opening malicious malware attachments to spam emails that appeared to contain invoices, job offers, security warnings and other legitimate files.
The ransomware encrypted data on the computers, demanding payments of $300 to $600 to restore access. Security researchers said they observed some victims paying via the digital currency bitcoin, though they did not know what percent had given in to the extortionists.
By the time they turned their attention to the United States, spam filters had identified the new threat and flagged the ransomware-laden emails as malicious, Thakur said.
Telecommunications company Telefonica was among many targets in Spain, though it said the attack was limited to some computers on an internal network and had not affected clients or services. Portugal Telecom and Telefonica Argentina both said they were also targeted.
Private security firms identified the ransomware as a new variant of "WannaCry" that had the ability to automatically spread across large networks by exploiting a known bug in Microsoft's Windows operating system.
The hackers, who have not come forward to claim responsibility or otherwise been identified, likely made it a "worm," or self spreading malware, by exploiting a piece of NSA code known as "Eternal Blue" that was released last month by a group known as the Shadow Brokers, researchers with several private cyber security firms said.
"This is one of the largest global ransomware attacks the cyber community has ever seen," said Rich Barger, director of threat research with Splunk, one of the firms that linked WannaCry to the NSA.
The Shadow Brokers released Eternal Blue as part of a trove of hacking tools that they said belonged to the U.S. spy agency.
Microsoft on Friday said it was pushing out automatic Windows updates to defend clients from WannaCry. It issued a patch on March 14 to protect them from Eternal Blue.