First, there were reports of Spain's largest telecom being hit with pop-up windows demanding a $300 ransom to access files. Then at least 16 hospitals in England's National Health Service were affected, locking doctors and nurses out of patients' records unless they paid up. Now comes word that networks around the world are under attack Friday."Currently, we have recorded more than 45,000 attacks of the WannaCry ransomware in 74 countries around the world, mostly in Russia," cyber security firm Kaspersky says. (We'll note that Kaspersky supports NPR and is a provider of security services for its IT systems.)Friday's attacks are being blamed on a piece of malware called WCry, WannaCry, or Wana Decryptor, that's now been tracked in large-scale attacks across Europe and Asia — particularly Russia and China — as well as attacks in the U.S. and South America, according to a map on the Malware Tech site.After the attack left medical providers in the U.K. scrambling to deliver vital services either without using computers or with machines that limped through the day, the U.S. Department of Health and Human Services issued a statement saying it's working to understand the threat and protect America's medical systems."We are also aware that there is evidence of this attack occurring inside the United States," the agency said in a message to public health entities Friday afternoon.Victims of the attack are confronted with a pop-up window that tells them their files are now encrypted and that they need to send $300 via the bitcoin cryptocurrency."You can decrypt some of your files for free," reads the message, which we're seeing today in a variety of languages. "But if you want to decrypt all your files, you need to pay. You only have 3 days to submit the payment. After that the price will be doubled."The window includes a countdown clock that threatens the files will be lost permanently in seven days.Wana Decryptor exploits a Windows flaw that was patched in Microsoft's Security Bulletin MS17-010 in March. But on machines that haven't been updated or patched, the malicious code encrypts all of an infected machine's files — and then spreads itself."Infection of a single computer can end up compromising the entire corporate network," Spain's National Cryptologic Center says.The malware is alleged to have been leaked or stolen from the National Security Agency, as the Bleeping Computer site reports. It was reportedly distributed by the Shadow Brokers, which claimed to have hacked an NSA-linked team of hackers last August.The Shadow Brokers group, which is suspected of having ties to Russia, posted Windows hacking tools last month."Activity from this ransomware family was almost inexistent prior to today's sudden explosion when the number of victims skyrocketed in a few hours," Bleeping Computer's Catalin Cimpanu writes.At least one Russian agency was hit by the ransomware — a fact that emerged after earlier conflicting reports. In an update after midnight local time, Russia's Interior Ministry acknowledged to state-run Tass media that its computers had been hit."As of now the virus has been localized," ministry spokeswoman Irina Volk told TASS. "There have been no inside information leaks from the Russian Interior Ministry's information resources."In the U.S., the Computer Emergency Readiness Team, or CERT, says it has "received multiple reports of ransomware infections in several countries around the world." The agency did not identify those countries.The Department of Homeland Security says it's coordinating with "international cyber partners" in the wake of the widespread attacks. When asked to confirm that Wana Decryptor has struck in the U.S., and at what scale, Acting Deputy Press Secretary Scott McConnell did not provide specifics."We routinely provide cybersecurity assistance upon request, including technical analysis and support," McConnell says. "Information shared with DHS as part of these efforts, including whether a request has been made, is confidential."Commenting on today's attack, Sen. Ben Sasse, a member of the Senate Armed Services Committee, says: