Con artists pushing tech-support scams have an arsenal of ways to lock up the browsers of potential marks. On Tuesday, a researcher disclosed a new weapon that freezes Google Chrome, which, by most measures, is the Internet’s most widely used browser.

The point of all the techniques is to render a browser unusable immediately after it displays a fake error message reporting some sort of security breach. Given the appearance of a serious crash that can’t be fixed simply by exiting the site, end users are more likely to be worked into a panic and call the phone number included in the warning. Once called, the scammers—posing as representatives from Microsoft or another legitimate company—stand a better chance of tricking the caller into providing a credit card number in return for tech support to fix the non-existent security problem. The scams are often transmitted through malicious advertisements or legitimate sites that have been hacked.