LONDON -- Employees booting up computers at work today could see red as they discover they're victims of a global "ransomware" cyberattack that has created chaos in 150 countries and could wreak even greater havoc as more malicious variations appear.
As a loose global network of cybersecurity experts fought the ransomware hackers, officials and experts on Sunday urged organizations and companies to update older Microsoft operating systems immediately to ensure they aren't vulnerable to a more powerful version of the software -- or to future versions that can't be stopped.
The initial attack, known as "WannaCry," paralyzed computers that run Britain's hospital network, Germany's national railway and scores of other companies and government agencies worldwide in what was believed to be the biggest online extortion scheme so far.
Microsoft blamed the U.S. government for "stockpiling" software code that was used by unknown hackers to launch the attacks. The hackers exploited software code from the National Security Agency that leaked online.
New variants of the rapidly replicating worm were discovered Sunday and one did not include the so-called kill switch that allowed researchers to interrupt its spread Friday by diverting it to a dead end on the internet.
Ryan Kalember, senior vice president at Proofpoint Inc. which helped stop its spread, said the version without a kill switch was able to spread but was benign because it contained a flaw that wouldn't allow it to take over a computer and demand ransom to unlock files. However, he said it's only a matter of time before a malevolent version exists.
"I still expect another to pop up and be fully operational," Kalember said. "We haven't fully dodged this bullet at all until we're patched against the vulnerability itself."
The attack held users hostage by freezing their computers, popping up a red screen with the words, "Oops, your files have been encrypted!" and demanding money through online bitcoin payment -- $300 at first, rising to $600 before it destroys files hours later. The ransomware attack was particularly malicious, because if just one person in an organization clicked on an infected attachment or bad link, all the computers in a network would be infected, said Vikram Thakur, technical director of Symantec Security Response.
"That's what makes this more troubling than ransomware was a week ago," Thakur said.
It hit 200,000 victims across the world since Friday and is seen as an "escalating threat," said Rob Wainwright, the head of Europol, Europe's policing agency.
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