I downloaded five RAR archives that were supposed to contain MP4 videos, but I'm now concerned they could be malicious. I opened the archives with WinRAR and viewed their contents, which appeared to contain only MP4 files. I also opened one of the videos briefly to check whether it played correctly. NOD32 reported that the archives were clean, but I'm still worried about ransomware or another type of malware. How risky is this, and what additional steps should I take?
3 Answers
Check the actual file extensions carefully. Malware may be disguised with names such as “video.mp4.exe,” and some systems hide the final extension by default. Enable visible file extensions in File Explorer, avoid launching anything executable or using suspicious scripts, and delete the files if you don’t trust where they came from. You can also scan the extracted files with an up-to-date security tool.
Based on what you described, there’s no clear sign that you have ransomware. Ransomware generally needs to execute code before it can encrypt files; simply storing a RAR archive or viewing its file list normally does not do that. Keep regular offline or cloud backups, run another reputable on-demand scan if it would reassure you, and watch for warning signs such as renamed files, inaccessible documents, ransom notes, unusual CPU or disk activity, or unexpected security alerts.
A RAR file is just a container, similar to ZIP or 7z. The archive itself isn’t automatically dangerous, but the files inside it could be. If the contents really are only MP4 files, you haven’t run any executable files, and your antivirus scan was clean, the risk is relatively low. Still, don’t open anything from an untrusted source, and make sure WinRAR, your media player, Windows, and your security software are fully updated.
Media players can occasionally have vulnerabilities, so a specially crafted video could theoretically be dangerous. That’s uncommon, though, especially when the player and operating system are patched.