The silent threat in your inbox — why you should think twice before unzipping

We all deal with email attachments every day. Whether it’s an invoice from a contractor, photos from a family member, or a project file from a colleague, clicking “download” is second nature. But among the harmless documents and images, there’s a file type that security experts urge you to handle with extreme caution: the .zip file.

A .zip file is like a digital suitcase—it packs multiple files into one smaller, convenient package. But just like a real suitcase, you can’t see what’s inside until you open it. This “blind spot” makes it a favorite tool for cybercriminals.

Why Hackers Love .Zip Files

Hackers know that most email services scan attachments for viruses. However, malicious code hidden inside a .zip file (especially if the zip file is password-protected) is much harder for automated scanners to detect. This allows malware, ransomware, and spyware to sneak past your email’s defenses and land right in your inbox.

Once you double-click that zip file to see what’s inside, you might inadvertently run a script that infects your computer.

Minimizing Your Exposure

While some attachments are unavoidable, you can significantly reduce your risk by following a few active rules:

1. The Contact Rule: Never, ever open a .zip attachment from someone who is not in your contacts list. If an unknown sender sends you a “Invoice.zip” or “Photos.zip,” delete it immediately.
2. The “Unexpected” Rule: Even if the email comes from a friend or coworker, pause if you weren’t expecting it. Hackers often hijack email accounts to send malicious files to everyone in the victim’s address book. If your boss sends you a strange zip file with no context, text them to verify they actually sent it.
3. The Cloud Alternative: This is your best proactive defense. Ask senders if they can share documents via a cloud link (like Google Drive, Dropbox, or OneDrive) instead of an attachment.
   1. Why it’s safer: Cloud services automatically scan files for viruses before you download them. Plus, you can preview the file content in your browser without ever saving it to your hard drive, keeping malicious code at arm’s length.

Better Safe Than Sorry

If you absolutely must open a zip file, ensure your antivirus software is active and up to date. Right-click the file and select “Scan for viruses” before you try to open it.

It only takes one bad click to compromise your personal data. Treat every .zip file with a healthy dose of suspicion, and when in doubt, ask for a cloud link!