The Petya ransomware attack, which spread like wildfire through global networks last week, should provide a wake-up call to businesses, according to JLT.

The virus, activated at the click of an attachment, rendered computers unusable and demanded a payment to unlock systems.

Law firm DLA Piper and confectioner Cadbury were among Australian companies whose computers systems were shut down.

JLT Cyber Security Specialist Samuel Rogers told insuranceNEWS.com.au businesses that operate internationally seemed most vulnerable, due to their systems’ interconnectivity.

“It is critical for businesses and governments to identify their vulnerabilities and understand their systemic risks,” he said.

“There are a number of immediate steps organisations can take to help protect themselves, such as securing their firewalls, end user points, servers and email systems.”

Businesses also need an incident-response team and technical support partner in place.

While ransomware is among the oldest forms of malicious virus, dating back 20 years, Petya and the recent Wannacry bug stand out for how quickly they penetrate systems.

“It’s been designed to spread as quickly as possible across networks,” Mr Rogers said.

Businesses should undertake full scenario testing to guide them on what sort of cyber insurance they need. Establishing a maximum foreseeable consequential loss will help them determine their limit, he says.

He says it is “very tempting” for organisations to see cyber risk as purely an “IT problem”. Building a culture in which each employee plays a part protecting the business is vital.

After the attack Australian Cyber Security Minister Dan Tehan issued an urgent warning to small businesses to update their cyber security.

“All businesses should immediately update their Windows operating system with the latest security patches, and there are instructions on the Australian Cyber Security Centre website to do this,” he said.