By Marcos Colon

Following the global ransomware attack that impacted more than 200,000 organizations in 150 countries, many believed Windows XP machines were hit the most, but new data claims otherwise.

Experts at Kaspersky Lab have discovered that 98 percent of the machines infected by the WannaCry ransomware worm were running a version Windows 7.

In a tweet on Saturday, Costin Raiu, director of the global research and analysis team at Kaspersky Lab, shared some of the data that indicated Windows 7 machines were hit the hardest. “The Windows XP count is insignificant,” he tweeted.

In an interview with Dark Reading, Raiu shared specifics tied to the malware authors’ attack methods. “Their code worked only with Windows 7, Windows 7 x64 and Windows 2008 servers,” he said.

Raiu believes that while attackers could have activated support for targeting Windows XP, “it seems they didn’t,” according to the Dark Reading report.