Microsoft says it estimates that 8.5m computers around the world were disabled by the global IT outage.
It’s the first time a figure has been put on the incident and suggests it could be the worst cyber event in history.
The glitch came from a security company called CrowdStrike which sent out a corrupted software update to its huge number of customers.
Microsoft, which is helping customers recover said in a blog post: “We currently estimate that CrowdStrike’s update affected 8.5 million Windows devices.”
That’s the neat thing, Crowdstrike bypassed the rigorous testing process to get Kernel software updates signed by Microsoft by having the part that was tested and signed by Microsoft load another update file. Still unclear how Crowdstrike missed it before releasing it though.
This is a pretty good break down of what happened by a retired windows dev. Including how software operates between Kernel and user zones. The break down of what he thinks happened is about 6:40.