Q. Hello, Kim. I accidentally downloaded a file from an email address that I didn't recognize. It said the file was an MP3 file, but my computer has been acting funny ever since I downloaded it. Can someone hide a virus in an MP3 file?
-Ben, from Phoenix, AZ, listens to my national radio show on KFYI 550 AM.
A. While it's certainly possible to hide a virus in all sorts of file types, Ben, I don't think that's what happened here. I'm willing to bet you didn't hear any music when you tried to open that MP3.
That's because the file probably wasn't an MP3. Savvy scammers can manipulate file extensions to disguise the fact that they're really .exe files - or executable program files. That means a hacker could easily make a file that looks like "myphotos.jpg" but is really "myphotos.jpg.exe."
By the time you realize that the file you thought was a photo or music file is a program, Windows has already started installing the virus. If only you could have seen the real file extension before clicking!
Every modern version of Windows hides a file's extension by default. This was done to make file names look cleaner, but it makes this scam tactic much more successful. It's harder to tell what type of file you're actually about to click.
This setting is easy to change. Open any file folder and click "Organize" in the upper left corner. Go to "Folder and Search Options" and then click the View tab. Uncheck the box that says "Hide extensions for known file types."
File extensions will now appear automatically when you're looking at files in your folders. You can see a file's extension by right clicking the file and choosing properties, if you're still not certain.
This doesn't eliminate the fake file extension problem entirely, though. A savvy hacker can actually manipulate the name of a file so it appears backwards. This means the real file extension shows up somewhere in the file, just not at the end.
This is trickier to avoid, but it's possible. You just have to know what file extensions to avoid. .exe is the most common, but you have to watch out for .bat, .cmd, .com, .lnk, .pif, .scr, .vb, .vbe, .vbs, .wsh. Keep in mind these may show up backwards, too.
Sounds like too much to remember? Well, the easiest way to avoid this problem is to never download files from email with address that you don't recognize! Even if you do recognize the address, verify with the sender that they sent you a file.
Click here for links to free security software for on your computer and others that will keep your machine clean, too. Anti-virus software will detect these dangerous programs before you do.
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