The aviation sector saw 4,300 flight cancellations globally, out of which roughly 2,600 were US flights|Mary-Lynn|CC BY 2.0

A massive IT outage on Friday wreaked havoc across multiple sectors worldwide, affecting banks, grounding flights, payment systems, healthcare and emergency services.

Companies are recovering from the incident, which is believed to be the largest IT outage in history. It originated after an update from the cybersecurity company CrowdStrike that affected Microsoft Windows devices.

The update gave millions of Windows computers the dreaded “blue screen of death” across the US, China, and Australia, affecting over 20,000 CrowdStrike subscribers. Mac and Linux systems were unaffected.

Microsoft and CrowdStrike deployed fixes immediately. But industries across sectors suffered.

Travel disruptions
The aviation industry was notably impacted, with 4,300 flights canceled globally out of which roughly 2,600 were US flights. Delta Air Lines had to cancel 20% of its fleet. More than 11,000 flights were delayed. The outage affected approximately 40% of global air traffic. More than 9,000 flights coming into or out of the US were delayed.

Hospitals and emergency services
Some of the largest hospitals in the US and Europe couldn’t perform surgeries. Providence and Services especially felt the scale of the outage as it affected 20,000 patients of the nation’s largest nonprofit healthcare systems.

Banks
Traders at several financial institutions couldn’t execute orders. Stock exchanges in New York, London and Tokyo saw a 20% drop in trading volume. Payments experienced a 30% decrease in transition success rates.

Government
Disruptions extended to emergency services with delays reported at 911 call centers and issues at blood donation centers.

The outage also disrupted shipping, which may negatively impact the supply chain.

What is CrowdStrike?
A Texas-based cybersecurity firm develops software to detect and block hacks for several Fortune 500 companies, including Amazon and Microsoft. Valued at $83 billion, the company faced issues with a Falcon platform update that triggered widespread crashes.

CEO George Kurtz stated that it was not a security breach or cyberattack. Microsoft has removed the affected update and is collaborating with CrowdStrike to resolve the issue. 

CrowdStrike’s shares fell 11%, while competitors SentinelOne and Palo Alto Networks saw gains. President Biden and the US Cybersecurity and Infrastructure Security Agency reported that hackers exploited the outage for malicious activities.