How to spot a disguised download
A disguised download is a harmful program dressed up to look like a safe file such as a document or an image.
The trick behind a disguised download
Most people relax when they see a familiar file: a PDF invoice, a photo, a spreadsheet. Attackers build a program and give it that look. You think you are opening a document. In fact you are running software a stranger wrote.
Check the real file type
Look past the icon and the first part of the name. What matters is the true ending.
- Learn the endings that run code. On Windows these include exe, scr, bat, cmd, com, msi, and js. A document should not end in any of those.
- A zip or rar file can hide a program inside. Opening the archive is fine, running what is inside without checking is the risk.
- Turn on file extensions in your system settings so the ending is always visible.
- A one-page PDF that arrives as a large file, or a video of a few kilobytes, does not add up.
Check where it came from
- Download apps from the maker's site or the built-in store, not from a mirror or an ad.
- A download that begins without a click, the moment a page loads, is a warning sign.
- An unexpected invoice, receipt, or resume from a stranger is a common way malware spreads.
- A brand name buried inside a longer domain, like update-adobe-viewer.net, is not the real brand.
How to protect yourself
- Do not open a file you did not expect, even from a name you recognize. Ask the sender through a separate channel first.
- Keep your browser and system updated, and scan a file you are unsure about before opening it.
- When in doubt, delete it. A file you do not open cannot harm you.
Fish Catcher's download guard warns you in plain language when a download is not what it claims to be, such as a program pretending to be a PDF. It never blocks the download.
Common questions
The file has a document icon. Doesn't that prove it is a document?
No. An icon is just a picture, and any file can carry any icon. Trust the ending, not the picture.
Is it dangerous to download a file, or only to open it?
Downloading is usually harmless on its own. The risk comes when you open or run it, and that pause is your chance to check.
A file downloaded by itself when I visited a page. What should I do?
Do not open it. Delete it. If you are unsure whether it ran, scan your computer and change important passwords from a device you trust.