Contact 2: Protecting yourself from massive, global ransomware attack

ST. LOUIS (KTVI) - It is one of the biggest cyber attacks in history affecting 150 countries and infecting more than 300,000 machines.

The "wannacry" ransomware attack is spread through email when a user clicks a malicious link, crippling computers across the globe, from government to businesses. Its reach expanded as people returned to work on Monday.

"We're bringing all of the capabilities of the U.S. government to bear on this issue and are working side-by-side with our partners in the private sector and our international partners," said Thomas Bossert, assistant to the president for Homeland Security and Counterterrorism.

"Anything that connects to the internet is a point of attack obviously," said Flavio Esposito, a computer science professor at Saint Louis University.

Esposito explained how an attack like this begins.

"The attacker gets information about who you are, through your social media, your browser history, not only you, your company, your enterprise, and then gets in with an email or a browser plug-in," Esposito said.

The virus takes control of a user's computer and demands a ransom, which—if paid—theoretically would then restore access. It's something both Esposito and the White House claim is a waste of money.

"The FBI reported that even if you pay, in some cases, they won’t release anything," Esposito said.

Even though the spread of the virus has been slowed, Esposito shared this advice.

"Update and upgrade (your computer) as much as you can," he said.

That means updating your software to the latest version and backing up all files on the cloud or a hard drive not connected to your computer.

It is still unclear who is responsible for this attack.