The recent CrowdStrike outage affected approximately 8.5 million devices – less than 1% of Windows machines worldwide – according to a blog post by David Weston, Microsoft's vice president of enterprise and operating system security.
These are the first hard numbers released by Microsoft and CrowdStrike about the scale of yesterday's outage, which was caused by an update to CrowdStrike's cybersecurity software that crashed Windows machines (Mac and Linux devices were not affected).
Although the number of affected devices was relatively small, the disruptions were widespread and global, affecting banks, retailers, brokerages, rail networks, and more. Airlines grounded flights worldwide.
“The percentage is [of affected devices] “While small in scale, the widespread economic and societal impact reflects CrowdStrike's use by companies that operate many essential services,” Weston wrote.
He declined to say what percentage of Windows devices with CrowdStrike software were affected, and it's important to remember that even a single computer crash can take down an entire network or data center.
Weston also wrote that while “this is not a Microsoft incident,” the company is working with CrowdStrike on the issue. Systems could take longer to restore if manual fixes were required for all affected computers, but Weston said Microsoft and CrowdStrike are developing “scalable solutions that will help Microsoft's Azure infrastructure accelerate fixes,” and are also working with Amazon Web Services and Google Cloud Platform.