Blue screen of death: Underlying cause of outage fixed, says Microsoft

A worldwide tech outage crippled industries from travel to finance on Friday before services started coming back online after hours of disruption, highlighting the risks of a global shift towards digital, interconnected technologies.

A software update by global cybersecurity firm CrowdStrike appeared to have triggered systems problems that grounded flights, forced some broadcasters off air and left customers without access to services such as healthcare or banking.

U.S. President Joe Biden had been briefed on the outage, a White House official said. ?

CrowdStrike CEO George Kurtz said on social media platform X that a defect was found "in a single content update for Windows hosts" that affected Microsoft's customers and that a fix was being deployed.

Microsoft said later on Friday that the issue had been fixed. ?

"We're deeply sorry for the impact that we've caused to customers, to travellers, to anyone affected by this, including our company," Kurtz told NBC News' "Today" programme.

"Many of the customers are rebooting the system and it's coming up and it'll be operational," Kurtz said. "It could be some time for some systems that won't automatically recover." CrowdStrike shares plunged as much as 14.5% shortly after the Wall Street open before paring losses to trade down 8.5%. ?

Its cyber rivals were up, with SentinelOne 3.6% higher and Palo Alto Networks up 1.7%.

Microsoft was down 0.2%. ?

"Earlier today, a Crowdstrike update was responsible for bringing down a number of Windows systems globally. We are actively supporting customers to assist in their recovery," Microsoft chief communications officer Frank Shaw said in a post on X.

But even as companies and institutions began restoring regular services, experts said the cyber outage revealed the risks of an increasingly online world. ?

"This is a very, very uncomfortable illustration of the fragility of the world's core Internet infrastructure," said Ciaran Martin, professor at Oxford University's Blavatnik School of Government and former head of the UK National Cyber Security Centre. While the core problem appeared simple, which should make it short-lived, its immediate impact was remarkable, Martin said.