Rent it for $3.99 on Amazon, Apple TV, or YouTube, or use a free trial on a legitimate service. Your computer’s antivirus software—and your viewing experience—will thank you.
Historically, movies like IT cycle in and out of the libraries on Tubi and Pluto TV. While not always available for free, it's worth checking these apps as they often host New Line Cinema titles for limited-time "free-to-watch" windows. it movie free 2017