Professor Ciaran Martin, former CEO of the National Cyber Security Centre, described the global crisis as the “mother of all IT failures”.
He believes the chaos was caused by an “accident” rather than a deliberate cyberattack by hostile actors, but is monitoring the situation.
He said BBC According to Radio 4, this software error “seems to be the most likely hypothesis at the moment, but it is evolving very quickly”.
He added: “There is a very well-known company in the cybersecurity space called CrowdStrike, which many large companies use for all sorts of corporate network protection.
“They have a line of products under a brand they call Falcon and their Falcon sensor update, which many companies use to detect threats, appears to have been misconfigured in such a way that it breaks Windows.
“So if a company uses both CrowdStrike and Windows for its operating system, it seems like they get what professionals call the blue screen of death and Windows doesn't work.
“That's why airlines are unable to process the data, and why Sky has been unable to release it.
“These complex systems always operate interdependently, so for cybersecurity to do its job, it must be able to interact with Windows.
“Companies spend a lot of time, money and effort on both sides of this equation, making sure they are compatible.
“You have to be careful not to destabilise other parts of the network and most of the time it works.
“Sometimes it's not. It's very rare that it's this serious. If it was a stroke, it would be so serious.
“We assume it was an accident, it is very plausible that it was an accident until evidence to the contrary emerges.”
