Monday, October 11, 2010

File Extensions - everything Microsoft loves to hide, or, how viruses work.

Now to be fair to Windows, I love it. I think it's a great, if highly flawed, operating system. I love Linux too, but it's a different kind of love. My biggest gripe with Windows, however, isn't that it's closed source or that it allegedly contains some sort of highly controlling DRM (as near as I can tell, the only DRM in Windows is DRM to prevent (usually unsuccessfully) piracy of Windows itself, which I suppose is fair enough). It's the treatment of  file extensions.

Now for those of you who have somehow stumbled upon a tech blog without knowing what a file extension is, well, its at the end of the filename and indicates to the computer what it should do with a file when you click it. If the file extension is, say, .jpg, it opens it in Windows Picture Viewer or whatever else you have set as your default for .jpg files. A .jpg file is a picture file, thus it opens with picture programs. Likewise, if its a .doc or .txt file it opens in a text program, like Microsoft Word or Openoffice.

The reason you, Mr. Joe Enduser, have never heard of this is because Windows, by default, hides file extensions, as if Microsoft actually wants its customers to not have a clue how their computers work (whether this is true or not is another matter). Whoever made this decision should be tarred and feathered, because he is responsible for millions if not billions of dollars of wasted income caused by people not knowing what a file extension is.

But how, exactly, does this default setting waste so much money? Simple. Viruses. See, Microsoft's excuse for this whole debacle is that all files are displayed next to an icon, a small picture indicating loosely what sort of file it is. A text file will have a  piece of paper, a picture will have a picture frame, etc. This is all well and good, but the problem is that the icon can be changed. The icon can lie. Usually, what happens is, you get ahold of a file somehow, and the icon looks just like the icon for a picture file, so you click the file to see what it is.

If you run XP, nothing happens. If you run Vista or 7, you get a warning screen which you click through like a zombie, since after all all you're doing is looking at a picture. Then nothing happens. In both instances something does happen, but you can't see it.

Here's what happens. That picture you clicked wasn't a picture at all. it was, in fact, a .exe file. An executable file. .exes are unique in that instead of opening a program, they are a program, just like the web browser you are viewing this in. Only this program is a virus. It implants itself in your computer, creating another .exe and hiding it in your computer, and setting that program to run at startup, hiding in the background. and then it wreaks havok, with symptoms depending on the virus.

Obviously this isn't the only way viruses spread, but it's probably one of the biggest, and it is literally all Microsoft's fault. So change your settings to show extensions!


  1. In Vista, open a folder and go to Tools -> Folder Options. Under the 'view' table, uncheck "Hide extensions for known file types".

  2. You are correct, but for that to happen you need a menu from which to select "tools" and that is also not displayed in vista/7 by default. you have to g to folder options from the control panel.