Ransomware affects 150 countries, businesses cautioned for future cyber attacks

European officials said at least 100,000 organizations in 150 countries were affected by global ransomware attack.

The cyberattack that's already hit tens of thousands of people around the world could cause even more problems this week.

It is possible more damage was done over the weekend, and we'll find out as people get back to work tomorrow.

On Sunday, experts are urged organizations and companies to update their operating systems immediately to make sure they're not vulnerable to another, more powerful version of the malicious software that hit about 200,000 victims worldwide since Friday. British Prime Minister Theresa May weighed in, "Europol has said that it is unprecedented in terms of the scale of the cyber-attack that has taken place. The National Cyber Security Centre is working with all organizations here in the U.K. that have been affected."

James clapper, former director of national intelligence

"Ransomware is something that we're going to see more and more of. So this is a very serious, serious problem. And I think it's going to grow," said former director of National Intelligence, James Clapper in an interview with ABC.

The attack is believed to be the biggest online extortion scheme ever recorded. It held users hostage by freezing their computers, encrypting their data, and demanding money through online payment. Then hours later, it destroyed victims' computer files. At a hearing on the issue, U.S. Senator John McCain said the U.S. needs to take a tougher stance to defend ourselves.

“We should consider developing a coast guard-like hybrid organization that can defend our territorial cyber boundaries, be our first responders and if necessary gracefully transition and support DOD, DHS, or FBI depending on the situation,” he said.

Cyber security experts said this vulnerability has been understood for months, yet too many groups didn't take it seriously.

Microsoft is one company that had made a fix in its updates of recent versions of windows, but many users didn't apply the software fix.