Global IT outage: what caused CrowdStrike outage and could other IT outages happen in the future?

• CrowdStrike say the outage is resolved for a “significant number” of computers.
• Around 8.5 million Windows devices were affected.
• Disruption expected to continue despite fix being issued.

The worst of a major IT global outage is over but leading cyber experts have warned that future incidents are “likely”. Millions of Windows devices were affected by an issue with a CrowdStrike update last week. 

A fix has since been rolled out after engineers worked around the clock to resolve the problem. The company has said that a “significant number” of computers have been “restored” as of Monday, 22 July. 

However disruption continues with GPs facing a “backlog” and flights still being cancelled. In the immediate aftermath of the outage, trains were delayed while banks also reported issues. 

But what caused the disruption and could similar outages happen again? Let’s take a look:  

What caused the CrowdStrike outage? 

The ‘worst’ global IT outage in years was caused by a software update. CrowdStrike was updating its Falcon sensor software in a move that was meant to make its clients’ systems more secure against cyberthreats, however it resulted in millions of Windows devices being disrupted. 

Reuters reports that a faulty code in the update files resulted in the widespread computer outages. Steve Cobb, chief security officer at Security Scorecard, which also had some systems impacted by the issue, said: “What it looks like is, potentially, the vetting or the sandboxing they do when they look at code, maybe somehow this file was not included in that or slipped through.” 

A fix has been rolled out to a “significant number” of the 8.5 million devices affected and they have been “resorted”. However there is a warning that the disruption caused by the outage could take a while to be resolved with NHS patients warned of a “backlog” at GP practices in England. 

Could a global IT outage happen again? 

The outage has been described as a “once-in-a-decade occurrence” by an expert, however others have warned that a similar mass disruption is “likely” to happen again in the future. 

Professor John Bryson is Chair of Enterprise and Economic Geography at Birmingham Business School said: “An IT disruption of this scale is highly unusual. This is a once-in-a-decade occurrence, or we all hope that it is a once-in-a-decade occurrence. For companies, it highlights the importance of backing up computer systems.” 

He added: “In other words, there needs to be an ability to provide services using paper rather than digital solutions. The real danger is that we all forget how to live and work in a pre-digital environment. Many have no idea how to work without computers and this makes it very difficult for companies to have paper-based backup systems in place."

However Professor Ciaran Martin, the former chief executive of the National Cyber Security Centre (NCSC) has warned that further mass IT outages are “likely” unless governments and industry work together to “design out” technological flaws. 

He told Sky News: “Until governments and the industry get together and work out how to design out some of these flaws, I’m afraid we are likely to see more of these again. Within countries like the UK and elsewhere in Europe, you can try and build up that national resilience to cope with this. But ultimately, a lot of this is going to be determined in the US.”

Dafydd Vaughan, Chief Technology Officer at Public Digital and co-founder of the UK Government Digital Service added: “Things will always go wrong: it’s a question of when, not if. Companies and national governments need to be prepared and take mitigating actions to minimise their exposure.

“Things move a lot faster now, with ever-growing cyber threats and ever-evolving technology to protect us. We get a lot of benefit from systems being connected and sharing information, but that does introduce risk too. We need to balance the gains against the risk and be aware that issues like this can – and increasingly will – happen.”

Have you been affected by the CrowdStrike outage - either directly or indirectly. If you’ve had your summer holiday disrupted or been unable to access your computer - contact our tech writer by emailing [email protected]