From blog.malwarebytes.com
Tech support browser lockers continue to be one of the most common web threats. Not only are they a problem for end users who might end up on the phone with scammers defrauding them of hundreds of dollars, they’ve also caused quite the headache for browser vendors to fix.
Browser lockers are only one element of a bigger plan to redirect traffic from certain sites, typically via malvertising chains from adult portals or sites that offer pirated content.