As the WannaCry ransomware continues to spread — albeit more slowly now — across the internet, security researchers are discovering more about the malware’s impact. New data from Kaspersky Lab today determines that more than 60 percent of computers infected were running Windows 7, countering the theory that the virus spread mainly across older, unsupported systems like Windows XP or Vista.
The Windows 7 majority is unsurprising, given the operating system’s ubiquity. Far fewer people have newer, less vulnerable operating systems such as Windows 10 (though Windows 8 owners received a free upgrade when it came out).
What is particularly interesting is how few computers running Windows XP were infected — so few, in fact, that Kaspersky deemed those machines statistically insignificant.
But statistical insignificance doesn’t fully cover WannaCry’s impact. For instance, if one of those few XP machines is operating a vital service on Britain’s NHS system, that arguably has far greater implications than 100 Windows 7 users losing family photos. So newer Microsoft operating systems might have caused the spread, but the highest-value targets, like the NHS system, are still running on legacy software.