Planes operated by several US airlines are being ordered to stay in the air due to major worldwide IT outages.
The American air regulator said American Airlines, Delta Airlines and United Airlines requested a ‘global ground stop’ in the early hours on Friday.
This means pilots in the air will be told not to land, while planes on runways cannot take off.
The NHS, Sky News and British rail operators are among a rapidly growing list of service around the world suffering disruption linked to malfunctioning anti-hacking software, with experts warning the chaos could last for days.
Air travel across the world is being affected, with issues including flight delays and check-in problems reported at airports from Manchester to Melbourne and by global airlines including Virgin.
New York Times reporter Jordyn Holman said she was stuck at Seoul Airport in South Korea waiting to board a Delta flight.
‘Unusually, the pilot came out to talk to a group of passengers, attributing the problem to a Microsoft platform,’ she said.
‘He said he had never had to make an announcement like this before.’
The US government warned that 911 lines were also affected in several states, urging people to instead directly call their local police or fire department.
A common problem appeared to be crashes of computers running on Microsoft’s Windows operating system, with users experiencing the infamous ‘blue screen of death’.
Downed services include Microsoft’s entire cloud service, which huge numbers of firms rely on across the globe, though the company says that outage has been resolved.
The chaos is being linked to cybersecurity software run by Texas-based firm CrowdStrike.
In a statement, CrowdStrike said it was ‘aware of reports of crashes on Windows hosts’ relating to one of its services.
The company said it had ‘identified’ and ‘reverted’ changes related to the problem but admitted machines could still crash or go offline.
It provided a four-step solution to the problem using Windows’ ‘Safe Mode’ to delete a file installed on their system as part of CrowdStrike’s software.
The chaos could last ‘several days’ due to how the problem has to be fixed manually, explains Professor Alan Woodward, a cyber security specialist at the University of Surrey.
Prof Woodward told Metro: ‘Based on what we know at the moment the main problem appears to be a result of an update by a product called Crowdstrike Falcon.
‘This is used to monitor the security of a large network PCs. To do that it downloads a piece of software called an “agent” to every machine. This monitors the PC and reports back problems.
‘This agent included a so called system file that means it is deeply embedded in the operating system. This update was corrupted in some way (we do not yet know what kind of error) so that as the PC tries to boot it comes across the corrupted file and can’t proceed – it puts up the so called Blue Screen of Death.
‘The product is used by large organisations that have significant numbers of PCs to ensure everything is monitored. Sadly if they lose all the PCs, they can’t operate or only at a much reduced service level.
‘The major frustration is that to fix the issue will require manual intervention on every affected PC. That will mean enormous delays in recovering and hence disruption for days to come.
‘Expect disruption in airports, railways, airlines, hospitals and a host of other institutions over several days. It raises questions about how this could be released without testing sufficiently.
‘The scale of this is truly global and because of the way it is likely to be fixed (manually rather than remotely) the disruption could be several days.’
In a statement given to ABC News, American Airlines said: ‘We’re aware of a technical issue with CrowdStrike that is impacting multiple carriers.
‘American is working with CrowdStrike to resolve the issue as quickly as possible and apologize to our customers for the inconvenience.’
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