In this article, extracted from my How to Open Suspicious PDFs Safely guide, I'll highlight ten warning signs that a PDF might be sketchy. PDFs are everywhere, but not all of them are trustworthy! Use these tips to spot suspicious documents and protect your computer from potential threats.

PDF Sandbox Demo

Nothing beats a live demo! When you're unsure if a PDF is safe, just open it in a sandboxed browser at browserling.com/browse. This remote browser (built by me and my team) lets you test PDFs without exposing your system to risk since it runs entirely outside your device. Try it out!

10 Signs a PDF Might Be Dangerous

🚩 Strange File Name

If the PDF's name looks random or has odd characters, it could be hiding something. Hackers often use confusing names to trick people.

🚩 Unexpected Sender

If you don't know who sent the PDF, be cautious. Scammers often pretend to be familiar contacts to get you to open unsafe files.

🚩 Request for Personal Information

If a PDF asks for passwords, credit card details, or other personal info, it's a huge red flag. Legit companies rarely ask for this over a PDF.

🚩 Spelling and Grammar Errors

Lots of typos or odd wording in the PDF? It might be from a scammer or hacker who's trying to trick you with a fake document.

🚩 Large File Size

A typical PDF is small, so a very large file could mean it's packed with hidden code or malware. If the file size seems way off, don't open it.

🚩 Embedded Links

Hyperlinks inside PDFs that lead to unknown websites are suspicious. If you see links, especially ones with weird URLs, avoid clicking them.

🚩 Unusual Icons

If the PDF has an icon that looks different from normal PDF icon, it might be fake. Scammers sometimes use fake icons to disguise unsafe files.

🚩Pop-Ups or Extra Files

If opening a PDF triggers pop-ups or suddenly downloads extra files, it's a warning sign. Regular PDFs don't behave this way.

🚩 PDF in the File Extension Twice

If the file name ends in something like ".pdf.exe" or ".pdf.zip," it's definitely suspicious. This is a trick to hide harmful files.

🚩 Tries to Run Scripts

PDFs shouldn't run scripts automatically. If your PDF reader alerts you that the document wants to run a script, this is a serious red flag. Malicious scripts can open back doors on your device.

What Is Browserling?

Browserling is a PDF sandbox service that lets you open and test PDFs safely in isolated, secure browsers and various PDF readers. By running outside of your own computer, it protects you from viruses or malware that might be hidden inside a PDF file. It provides a simple way to check PDFs without putting your device at risk.

Who Uses Browserling?

Browserling has now become the PDF testing platform of choice and it's used by hundreds of thousands of users around the world every month. Browserling's customers include governments, states, cities, banks, stock exchanges, universities, newspapers, Fortune 100, Fortune 500 companies, and private multi-billion dollar companies.

Browse safe!