The wi-fi connections of businesses and homes around the world are at risk, according to researchers who have revealed a major flaw dubbed Krack.

It concerns an authentication system which is widely used to secure wireless connections.

Experts said it could leave "the majority" of connections at risk until they are patched. The researchers added the attack method was "exceptionally devastating" for Android 6.0 or above and Linux.

A Google spokesperson said: "We're aware of the issue, and we will be patching any affected devices in the coming weeks."

The US Computer Emergency Readiness Team (Cert) has issued a warning on the flaw. "US-Cert has become aware of several key management vulnerabilities in the four-way handshake of wi-fi protected access II (WPA2) security protocol," it said. "Most or all correct implementations of the standard will be affected."

Computer security expert from the University of Surrey Prof Alan Woodward said: "This is a flaw in the standard, so potentially there is a high risk to every single wi-fi connection out there, corporate and domestic.

"The risk will depend on a number of factors including the time it takes to launch an attack and whether you need to be connected to the network to launch one, but the paper suggests that an attack is relatively easy to launch.

"It will leave the majority of wi-fi connections at risk until vendors of routers can issue patches."

Industry body the Wi-Fi Alliance said that it was working with providers to issue software updates to patch the flaw.

"This issue can be resolved through straightforward software updates and the wi-fi industry, including major platform providers, has already started deploying patches to wi-fi users.

"Users can expect all their wi-fi devices, whether patched or unpatched, to continue working well together."

It added that there was "no evidence" that the vulnerability had been exploited maliciously.

Tech giant Microsoft said that it had already released a security update.

BBC News