Do you know how to find malicious files once they are on your computer?There is a simple “trick” you can do to find such files.

One way that malware proliferates on PC’s is by hiding file extensions. Most computer operating systems (Window’s and Macintosh) hide this by default. A file extension is usually a 3 or 4 character extension to a file-name that helps designate what program can open the file. For example, a file named “mydocument.docx” has the docx file extension. And Microsoft Office (Word) opens this type of file.

Not showing this extension while you’re browsing through your files can surely be an issue. What hackers do is try to get you to run a malicious program on your computer system. They do this by disguising the malicious program as another type of a file, such as an image or document file, by simply changing that file extension and the icon of the file. And if the file extension is hidden by default, then that is big trouble.

For example, if a malicious hacker somehow (through email, usb drive, other OS vulnerability, etc.) were to get you to download and open “dog.jpg”, you might never have known that it was actually called “dog.jpg.exe” because the real extension is hidden by default. And an “exe” file is actually a program, not just any file, that can damage your computer or take it over if it’s malware!

This applies to Window’s or Mac OS’s.

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We won’t spend too much time getting you instructions to setup this “trick”. Some file extensions that cyber attackers would be delighted if you ran on your computer are:

how to find malicious files
Files are the convention we use to organize data on computers. They contain human readable text, computer data, or computer executable code (programs). These programs, if malicious, can be devastate a computer system or put it under the control of a bad guy.
  • .exe
  • .bat
  • .docm
  • .xlsm
  • .com
  • .ps1
  • .app

By no means is the list above comprehensive. They are just some common file extensions that run Windows or MacOS.

How do you find malicious files on your computer in the first place?

  • Downloaded files through email
  • Downloaded files through the internet, saved from your web browser
  • Someone else using your computer(s) doing the above.

If you would like to show your file extensions, instead of us reinventing the wheel, check out these following guides:

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