Microsoft says 8.5 million devices were affected by the CrowdStrike bug or 'less than one percent of all Windows devices' as new details emerge on Friday's tech meltdown

MADRID, SPAIN - JULY 19: A general view from Madrid-Barajas International Airport as passengers gather and wait due to the global communications outage caused by CrowdStrike, which provides cyber security services to US technology company Microsoft, on July 19, 2024 in Madrid, Spain. (Photo by Diego Radames/Anadolu via Getty Images)

(Image credit: Diego Radames/Anadolu via Getty Images)

If you were part of the endless legions of IT workers furiously fixing Windows machines over the weekend thanks to the CrowdStrike bug, I salute your service—and if you were affected by the disruptions to flights, hospital services, banking and more, I commiserate. Most of us, however, remained unaffected, as according to Microsoft only 1% of Windows devices fell victim to the bug.

Still, that's 8.5 million devices causing turmoil worldwide, and as a result, Microsoft says it deployed hundreds of Microsoft engineers and experts to work with customers to restore their stricken services (via The Verge). MS also engaged directly with CrowdStrike to work on a solution, with the company releasing its own, separate statement regarding some of the technical issues that caused the event.

At the core of the fault was a configuration file contained in an update for CrowdStrike's Falcon platform, which triggered a logic error that in turn caused a BSOD loop on Windows systems running Falcon sensor software.

The update was designed to "target newly observed, malicious named pipes being used by common C2 frameworks in cyberattacks", but instead threw some very important infrastructure into a loop, causing a gigantic knock-on effect.

How we did this in the old days:When I was on Windows, this was the type of thing that greeted you every morning. Every. Single. Morning.You see, we all had a secondary "debug" PC, and each night we'd run NTStress on all of them, and all the lab machines. NTStress would… pic.twitter.com/rZkvpujbcrJuly 20, 2024

The problem, in this case, is that this event was created by a CrowdStrike driver that passed WHQL testing but still possessed the capability to download and execute p-code that hadn't been signed by Microsoft. Essentially, a third-party driver at the heart of a system can still bring it down with a dodgy update, even if Microsoft's processes for its own updates have appropriate levels of testing and certification.

Well, it's all been a bit of a clusterfudge, hasn't it? Microsoft is unlikely to be happy that its name is once again in the headlines for server-related issues, although in recent years it's often been security breaches that have earned it criticism. As of now, the issue appears to have been fixed, at least, and perhaps some lessons have been learned for third-party updates in future.

Andy built his first gaming PC at the tender age of 12, when IDE cables were a thing and high resolution wasn't—and he hasn't stopped since. Now working as a hardware writer for PC Gamer, Andy spends his time jumping around the world attending product launches and trade shows, all the while reviewing every bit of PC gaming hardware he can get his hands on. You name it, if it's interesting hardware he'll write words about it, with opinions and everything.