The "accidental hero" who inadvertently stopped Friday's massive cyberattack that affected nearly 100 countries is a 22-year-old who lives with his parents, the Guardian reports. The British cybersecurity researcher—who's keeping anonymous to protect himself—found a nonsensical website address in the code for the ransomware holding victims' data hostage and causing chaos around the globe. He spent less than $11 to register the domain with the hope of monitoring the spread of the ransomware. But it turns out, registering the domain was a "kill switch" added by the creators of the ransomware in case they ever wanted to stop it themselves. For a more in-depth explanation, check out the 22-year-old's blog titled "How to Accidentally Stop a Global Cyber Attack."
But while the spread of the ransomware has been halted for now, the world's computer systems are far from in the clear. Cybersecurity expert Matt Suiche says whoever is behind the attack—their identity is still unknown—can simply update the ransomware and start again. "I'd even say this update probably already happened," he tells ABC News. There were 75,000 individual attacks across 99 countries Friday. CNN runs down the victims, which include FedEx, Nissan, the Russian Central Bank, Britain's National Health Service, and Spain's Telefonica. Most of the attacks were in Russia, Ukraine, and Taiwan. (Read more cyberattack stories.)