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
- 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.
- Deep Scanning: You can run full system scans that specifically include archives. This takes longer but is more thorough.
- 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
- 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’.
- Run a Full Scan: Perform a full system scan, ensuring it includes archive files.
- In Windows Security, select ‘Full’ under Scan options.
- 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?
- Update Definitions: Make sure your antivirus has the latest virus definitions.
- Most antivirus programs update automatically, but you can usually force an update manually.
- Archive Type Support: Verify that your antivirus supports the archive format you’re using.
- 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.
- 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.