The most alarming part of the keyword is the word Legitimate movie watching does not require an "install." You stream on Netflix, you download via Amazon Prime's offline feature, or you purchase a digital copy from iTunes/Google Play. You never "install" a movie file.
If you need to "install" a movie for offline viewing, every legitimate platform offers this:
None of these require sketchy third-party installers.
For a better viewing experience with high-quality resolution and no security threats, consider these platforms: