: Upload the file to a multi-engine scanner like VirusTotal to see if it is flagged by antivirus software.

: In rarer cases, a specifically crafted MP4 can exploit vulnerabilities in a video player (such as VLC or Windows Media Player) to execute code once the file is opened.

: Perform a full system scan with trusted tools like Malwarebytes or NordVPN File Checker to detect any unauthorized changes.