Almost all Windows devices are back online

A report this week found that one in four Fortune 500 companies were hit by the outage, costing them an estimated $5.4 billion.

Nearly a week after a software update caused what may be the worst IT outage in history, Crowdstrike CEO George Kurtz says nearly all of the affected Windows devices are now online.

Yesterday (July 25) in a LinkedIn post, Kurtz said that more than 97% of Windows sensors are now online, but the US cybersecurity firm “is not done yet.”

“I am deeply saddened by the disruption this outage has caused and I personally apologize to everyone affected. While I cannot promise perfection, I can promise a response that is focused, effective, and with a sense of urgency,” he wrote.

“Our data recovery efforts have been strengthened by developing automated data recovery techniques and mobilizing all of our resources to support our customers. We have published a preliminary incident report detailing how this happened and what measures we are taking to prevent such incidents in the future.”

The outage, which occurred on July 19, quickly turned into a global crisis. Various sectors – notably airlines, banks and healthcare – suffered serious disruptions after the outage caused Microsoft computers to shut down.

It was quickly traced to a flawed cybersecurity update from Crowdstrike. The company released a patch that afternoon and assured users that it was not a cyberattack.

In a post-incident review, Crowdstrike said the outage was caused by a bug in its system that allowed “problematic content data” to pass verification.

“Based on testing performed prior to initial deployment… confidence in the checks performed in the content validation module and previous successful deployments of IPC template instances, these instances were deployed to production,” the report reads.

“When received by the sensor and loaded into the interpreter, problematic content in the channel 291 file caused an out-of-bounds memory read, triggering an exception. This unexpected exception could not be handled gracefully, causing the Windows operating system to crash.”

A report released this week found that one in four Fortune 500 companies were hit by the outage, costing them an estimated $5.4 billion (excluding Microsoft, which was more directly linked to CrowdStrike).

According to the Parametrix report, Fortune 500 companies in the healthcare sector will suffer the largest direct financial loss, followed by banking. Together, they will likely suffer more than half the loss, despite accounting for just one-fifth of Fortune 500 revenue.

“Crowdstrike is committed to our mission of stopping breaches with a renewed focus on customer control and resilience,” Kurtz added. “Customer obsession has always been our guiding principle, and this experience has only strengthened our resolve.”

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