Nearly 5 million users reported Web troubles to Downdetector during CrowdStrike glitch

29 July 2024

A routine software update performed by cybersecurity firm CrowdStrike on 19 July caused what some believe to be the largest tech outage in IT history. Microsoft reported that the outage impacted around 8.5 million Microsoft Windows devices causing the devices to display the blue screen of death.

The outage resulted in major airlines being forced to ground their flights, TV news stations going off the air, hospitals cancelling medical procedures, and banks being unable to transfer customers’ funds.

Downdetector by Ookla, which monitors real-time performance for thousands of popular web services globally, had a front row seat to the 19 July outage. Nearly 5 million users flocked to Downdetector.com to report on the status of different websites, which was more than three times the average number of users that typically visit the Downdetector site every day.

All major sectors of the economy see spike in outage reports

Downdetector reported surges in outage reports across a variety of sectors, from emergency services, which saw the largest increase over its daily average, at 68x, to airlines, retail, banking, and even dating services.

Not surprisingly, Microsoft bore the brunt of user reported outages. Microsoft witnessed a 42x increase over its daily average, while Microsoft 365, its cloud-based productivity suite, saw user reports increase 18x. Microsoft Azure was also impacted, with user reported outages up 21x.

Beyond software providers, transport, airlines, ride sharing and even e-commerce and delivery services saw large spikes in outage reports. Tesla saw an increase of 12x over its daily average, while user reported outages for Uber were up 57x, and Uber Eats experienced a 41x increase. Amazon witnessed a 14x increase in outage reports, while DHL and Fedex saw 6x and 4x increases respectively.

Airline sites hit with 50% rise in reports

The airline industry was significantly impacted by the Crowdstrike-induced outage. OAG, a provider of digital flight information, reported that the world’s 20 largest airlines cancelled nearly 10,000 flights between 19-21 July.

Delta Airlines was by far the most impacted of the large global airlines, having cancelled 5,300 flights since the outage started. The airline is now under federal investigation for how it’s handling the delays and cancellations.

Not surprisingly, Downdetector’s data on the various airline websites shows that the airline category of websites experienced more than 50 times the average number of user reports on July 19, with Delta Airlines and Ryanair (a low-cost airline covering Europe), leading this sector. In fact, Delta alone experienced a 92x increase in user reports on July 19 compared to its typical daily average and United Airlines saw a 57x increase. Delta was still experiencing more than 6x the average daily number of user reports four days after the outage on 23 July.

Digital banks and financial companies also struggled to serve their customers during the outage. Visa received more than 64,000 user reports on July 19 compared to its typical daily average of just 1,500 and online bank TDBank also saw its user reports increase to more than 56,000 on the 19th compared to its typical daily average of 240 reports.

Although most company websites have rebounded, the outage showcased just how vulnerable today’s websites are to software glitches and updates.