Antivirus & Archive Files: Can it delete inside?

TL;DR

Yes, a modern antivirus can detect and delete files within an archive (like a ZIP or RAR file) without needing to extract them first. This is thanks to technologies like on-access scanning and deep scanning. However, it depends on the antivirus software, its configuration, the type of archive, and whether the archive is password protected.

How Antivirus Scans Archives

1. On-Access Scanning: Most antivirus programs constantly monitor files as you access them. When you open an archive, or a file within it, the antivirus checks it immediately.
2. Deep Scanning: You can run full system scans that specifically include archives. This takes longer but is more thorough.
3. Archive File Support: Antivirus software needs to be able to understand different archive formats (ZIP, RAR, 7z, etc.). Most support common ones.

Steps to Check if Your Antivirus Scans Archives

1. Check Settings: Open your antivirus program’s settings. Look for options related to archive scanning or file types. The exact location varies depending on the software.
   • Example (Windows Security): Go to Virus & threat protection > Scan options. You should see an option like ‘Scan archives’.
2. Run a Full Scan: Perform a full system scan, ensuring it includes archive files.
   • In Windows Security, select ‘Full’ under Scan options.
3. Test with an EICAR Test File: The EICAR test file is harmless but detected as a virus by most antivirus programs. Place it inside a ZIP archive and scan the archive.
   • You can download the EICAR test file from the official EICAR website.

What if Your Antivirus Doesn’t Detect Files Inside?

1. Update Definitions: Make sure your antivirus has the latest virus definitions.
   • Most antivirus programs update automatically, but you can usually force an update manually.
2. Archive Type Support: Verify that your antivirus supports the archive format you’re using.
3. Password Protection: Password-protected archives may not be scanned by some antivirus programs unless you provide the password.
   • Some antivirus software will prompt you for a password before scanning a protected archive.
4. Antivirus Configuration: Double-check your antivirus settings to ensure archive scanning is enabled and configured correctly.

Command Line Scanning (Advanced)

Some antivirus programs offer command-line tools for more control.

<antivirus_command> scan "/path/to/archive.zip"

(Replace <antivirus_command> with the appropriate command for your software and adjust the path accordingly.)

Important Considerations

• False Positives: Antivirus programs can sometimes incorrectly identify legitimate files as threats.
• Multiple Layers of Security: Don’t rely solely on antivirus. Use a combination of security measures, including firewalls and safe browsing habits.