This is how the biggest IT outage of all time occurred

According to experts, the largest IT outage of all time occurred on July 19, 2024. The reason: A faulty software update from the cybersecurity company Crowdstrike had paralyzed numerous Windows systems at airports, banks, hospitals and emergency services. The background.

The platform of the US cybersecurity company Crowdstrike is actually intended to protect cloud applications and programs from developers such as Microsoft. But a software update paralyzed numerous areas of public life on Friday, July 19, 2024. These include airports, banks, hospitals and emergency calls.

Crowdstrike: Software update paralyzes airports and banks

The result: numerous Microsoft systems could no longer boot up and displayed a so-called blue screen. This in turn restricted operations at numerous airports, banks and hospitals. In the USA, the emergency services were temporarily unavailable.

Crowdstrike officially confirmed the incident on the same day and said it had fixed the error. The problem: This does not automatically mean that all systems will immediately run smoothly again. Because once a PC is affected and is stuck in the boot loop, it can no longer install automatic updates or be remotely maintained.

Meanwhile, Crowdstrike CEO George Kurtz has also commented on the incident in a post on X (formerly Twitter). According to him, the problem is not a security incident or cyber attack. Furthermore, only Windows systems and devices are affected.

Crowdstrike has now not only identified the problem but also isolated it. Kurtz said: “We refer our customers to the support portal to get the latest updates and will continue to provide full and continuous updates on our website.”

Kernel problem affects millions of Windows computers

According to reports, the faulty Crowdstrike update of the company's own Falcon software triggered a driver error in the kernel of the affected devices. Background: The kernel is a central element of an operating system. It is considered the interface between hardware and software.

When you shut down a computer, the kernel is the first thing to be loaded into memory. Only then do other parts of the operating system follow.

In concrete terms, this means that if there is a problem with the kernel, the rest of the system cannot boot up. In the case of the faulty Crowstrike update, this resulted in numerous computers getting stuck in the so-called blue screen.

Crowdstrike: The biggest IT outage of all time?

Microsoft has now also commented on the incident. According to an official blog post from the company, a total of 8.5 million Windows devices were affected by the problem. Systems with the cloud operating system Windows 365 were also affected.

Correcting the error would have been extremely complex, especially in the cloud area. However, Microsoft also announced that only one percent of all Windows computers worldwide were affected by the faulty update.

The fact that the economic and social impacts were nevertheless so serious and far-reaching is shown by the fact that many companies and institutions in the area of ​​critical infrastructure use the software provider CrowdStrike. As the online magazine Techcrunch reported that around 60 percent of all Fortune 500 companies are Crowdstrike customers.

According to experts, this is probably the largest IT outage of all time. Even though air traffic in particular has now returned to normal, many companies are still struggling with the consequences. According to the Federal Office for Information Security (BSI), it is still unclear “how the faulty code got into the Crowdstrike update”. The BSI is in intensive contact with the company.

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