A coalition of tech companies including Facebook, Google, AOL, Twitter and Yahoo has formed a new partnership to take down bad and malicious advertising on the Internet. The group’s new website, TrustInAds.org, lets users report bad ads to the companies. The site also published a report detailing what Facebook and Google have done to combat a particularly malicious strain of bad ads that takes advantage of users by offering fake tech support.

“Among the legitimate online ads offering valuable tech support services to consumers are some from bad actors attempting to prey on unsuspecting Internet users,” said Rob Haralson, Executive Director of TrustInAds.org.  “These bad actors, often highly sophisticated, go to great lengths to hide under the radar from the manual reviews and automated filtering technologies used to catch fraudulent ads.”

According to the report, Google and Facebook have created new signals in their enforcement algorithms to catch bad ads while continuing to rely on user complaints and manual reviews to identify the parties behind these attacks. Google even called 1-800 numbers listed in the ads and posed as users seeking tech support help to get to the bottom of the scams.

To protect yourself from falling prey to fake tech support, TrustInAds.org recommends you never give out passwords over the phone, check up on the party you’re contacting and refuse to download software if prompted. Also, if you think you have fallen prey to a malicious ad, you can use the TrustInAds.org page to report it.