Japan said on Friday it will set up a team to simulate cyberattacks using AI to identify weaknesses in technology systems, as organisations scramble to curtail risks from flaws in the PHP programming language that underpins much of the internet, Reuters reported.

Government and company websites across the world went offline this week after the disclosure of critical vulnerabilities in PHP prompted millions of hacking attempts, forcing operators to rush to protect or temporarily shut down their systems. Emergency shutdowns from Tokyo to Helsinki hit banking, airline, rail, tax and government services.

Highlighting the extent of the disruption, SoftBank, Japan's third-largest mobile carrier with more than 30 million smartphone customers, said on Friday it was suspending its emergency alert system for mobile users while it addresses a PHP vulnerability — meaning customers will not receive early warnings for earthquakes, tsunami alerts or evacuation information through that system, though earthquake warnings remain available through services such as an app from its Yahoo business, Reuters reported.

"An attack can succeed by getting through just one hole … for that reason it's important we shift our mindset and think from the perspective of the attacker," Japanese industry minister Ryosei Akazawa said on Friday. "Defenders also need to make use of AI and respond proactively, staying one step ahead."

Companies including brokerage Nomura, lender Mitsubishi UFJ Financial Group, airline ANA and East Japan Railway (JR East) temporarily suspended some internet services, as did Japan's Ministry of Finance, National Tax Agency and Meteorological Agency. JR East said on Friday some group services had resumed, while others would be restored once confirmed safe.

Not everyone was convinced the response was fast enough. Nobuo Miwa, president of Tokyo-based cybersecurity firm S&J Corp, said the government response was too slow, describing it as "like trying to take on a bomber with a bamboo spear," Reuters reported.