Professor Ciaran Martin, former CEO of the National Cyber Security Centre described the global crash as the “mother of all IT outages”.
He believes the chaos has been caused by an “accident” rather than a deliberate cyber attack by hostile actors but is monitoring the situation.
He told BBC Radio 4 that software error, “seems the most likely assumption at the moment but it’s developing so quickly.”
He added: “There is in cybersecurity a very well known company called CrowdStrike that a lot of major companies use for all sorts of corporate network protection.
“They have a range of products under a brand they call Falcon and their Falcon sensor update, which a lot of companies will use to detect threats, seems to have been misconfigured in such a way that it wrecks Windows.
“So if a company is using both CrowdStrike and Windows for its operating system, it seems that they get what people in the trade call the blue screen of death and Windows doesn’t work.
“That’s why airlines aren’t able to process, why Sky hasn’t been able to broadcast.
“These complex systems always operate interdependently so for the cybersecurity to do its job it has to be able to interact with Windows.
“Companies spend a lot of time money and effort on both sides of that equation, making sure that they’re compatible.
“You have to make sure you don’t destabilize other parts of the network and most of the time that works.
“Occasionally, it doesn’t. It’s very rare to be as serious as this. If this was an attack, it (would) be such a serious one.
“We assume that this is an accident, it’s very plausible that it’s an accident until evidence emerges to the contrary.”
