How to protect your computer from malware

CHICAGO (WLS) -- New malware attacks are affecting millions of computer users. How can you keep your computer from being corrupted?

Two major threats were discovered this week: a popular website stopped fake ads that tried to infect people who clicked; and another group of criminals who were allegedly using a new malware program were exposed by a security-firm based out of Chicago.

Sai Pothula works in IT and even he fell victim to a malware attack. His computer stalled after clicking on an untrustworthy ad.

"The computer was jammed. It will not allow you to do any work. Wherever you go, it will ask you to pay money," Pothula said.

After several attempts, Pothula got rid of the malware on his own, but the hackers may have had total access to his information.

Trustwave researchers in Chicago and Atlanta uncovered a new attack this week that experts say has infected 1.3 million people worldwide- 45,00 here in the U.S.

"These could be backdoors where they access your computer down the road, turn on the microphone, turn on the camera, view your browser history. It could be ransom ware in case they want to encrypt your hard drive and then charge you a ransom in order to de crypt it," Karl Sigler, Trustwave, said.

Users often get breached by clicking on "mal-vertisements" that lead them to a compromised website.

Yahoo, which gets almost 7 billion visits a month, was also hit this week. Malicious code potentially could have been downloaded after Windows PC users clicked on an ad. In reports, Yahoo said it quickly blocked the fake advertiser.

Stephan Dico fixes laptops at Chicago's Computerland in Lincoln Park. He's dealing with a lot of infected computers.

"We see them daily, like every 3, 4 of them daily. But more phone calls, 7-8 phone calls about malware," Dico said.

Dico said computer users should avoid clicking on ads that sound too good to be true, like pitches for wonder drugs, insider stock tips and cheap iPads. Also beware of other pop-ups saying that programs like Adobe need updated.

"If you are not 100 percent it is legitimate source, close everything," Dico said.

Technicians said consumers should also buy anti-virus software, which should also be updated regularly.

Not only will it cost you about 100 dollars to fix a malware attack but there is no telling what information the you are giving away on your own computer.

Yahoo released a statement following last week's malware incident:

Yahoo is committed to ensuring that both our advertisers and users have a safe and reliable experience. As soon as we learned of this issue, our team took action to block this advertiser from our network.

We take all potential security threats seriously. With that said, the scale of the attack was grossly misrepresented in initial media reports and we continue to investigate the issue.

Unfortunately, disruptive ad behavior affects the entire tech industry. Yahoo has a long history of engagement on this issue and is committed to working with our peers to create a secure advertising experience. We'll continue to ensure the quality and safety of our ads through our automated testing and through the SafeFrame working group, which seeks to protect consumers and publishers from the potential security risks inherent in the online ad ecosystem.