Global Cyber Attack Hits Hospitals, Companies

A global cyber attack leveraging hacking tools believed to have been developed by the US National Security Agency has infected tens of thousands of computers in nearly 100 countries, disrupting Britain's health system and global shipper FedEx.

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, Reuters reported.

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.

Researchers with security software maker Avast said they had observed 57,000 infections in 99 countries, with Russia, Ukraine and Taiwan the top targets. Some experts said the threat had receded for now, in part because a British-based researcher, who declined to give his name, registered a domain that he noticed the malware was trying to connect to, limiting the worm's spread.

But the attackers may yet tweak the code and restart the cycle.

The British-based researcher who may have foiled the ransomware's spread told Reuters he had not seen any such tweaks yet, "but they will."

Finance chiefs from the Group of Seven rich countries will commit on Saturday to join forces to fight the growing threat of international cyber attacks, according to a draft statement of a meeting they are holding in Italy.