MP4 Viruses: Are Your Videos Safe?

TL;DR

Yes, .mp4 files can contain viruses, but it’s not common. The virus isn’t *in* the video itself, but hidden within the file container or delivered through how you got the file. Keep your software updated and be careful about where you download videos from.

How MP4 Files Can Get Viruses

1. Malicious Code in the Container: .mp4 files are containers – like boxes holding video data, subtitles, and other information. A virus can hide within these extra parts of the file.
   • This is rare but possible.
2. Fake MP4 Files: The file might not be an .mp4 at all! It could be renamed to look like one, but actually contain a different, harmful program (like an executable).
   • Windows often executes files based on their icon and extension. A cleverly disguised file can trick you.
3. Downloaded from Untrustworthy Sources: This is the most common way to get a virus with an MP4.
   • Pirate websites, shady download sites, or suspicious email attachments are high-risk areas.
4. Vulnerable Software: Older versions of video players (like VLC or Windows Media Player) might have security holes that a virus could exploit when opening an MP4.
   • These vulnerabilities allow the virus to run code while processing the file.

How to Check for Viruses in MP4 Files

1. Scan with Antivirus Software: This is your first line of defence.
   • Run a full scan on your computer, including any folders where you store downloaded videos.
   • Make sure your antivirus definitions are up-to-date!
2. Use VirusTotal: This website scans files with multiple antivirus engines.
   • Go to VirusTotal and upload the MP4 file.
   • It will give you a report showing if any antivirus programs detect it as malicious.
3. Check File Properties (Windows): Right-click on the .mp4 file, select ‘Properties’, then go to the ‘Details’ tab.
   • Look at the ‘File type’. If it doesn’t say “MP4” or something similar, be suspicious.
4. Examine File Extension: Make sure the file extension is actually .mp4 and not something hidden (like .exe disguised as .mp4).
   • In Windows, you might need to enable ‘Show file extensions’ in Folder Options.
   • Go to Control Panel > Appearance and Personalization > File Explorer Options > View tab > uncheck “Hide extensions for known file types”.

How to Prevent MP4 Viruses

1. Download from Trusted Sources Only: Stick to reputable websites and official sources.
   • Avoid pirate sites, torrents, and unknown download links.
2. Keep Your Software Updated: Regularly update your operating system, video players (VLC, Windows Media Player), and antivirus software.
   • Updates often include security patches that fix vulnerabilities.
3. Be Careful with Email Attachments: Don’t open MP4 attachments from senders you don’t trust.
   • Even if the sender seems familiar, be cautious if the email is unexpected or contains suspicious links.
4. Use a Sandbox (Advanced): If you absolutely must open an MP4 from an untrusted source, consider using a sandbox environment.
   • A sandbox isolates the file so it can’t harm your main system if it’s malicious.
   • Windows has built-in features like Windows Defender Application Guard that can act as sandboxes.