Xls Viewer Which File Extensions Are Used By Viruses?

Ok, so what exactly is a file 'extension' anyway?

A file extension is the period + the last three letters of a file.

Some of these extensions are commonly, but not exclusively of course, used by viruses.

Here are some of the extensions most often used for virus files -

".exe" (Executable)

".scr" (Screen Saver)

".com" (Not the website, but the file-type)

".bat" (System file)

".sct" (Script File)

".ocx" (ActiveX Objects)

".dll" (Dynamic Link Libraries)

If you find a file ending in one of the above extensions in an email that you have been sent, or on a USB drive for instance, then just be a little cautious before opening it as it may not be what you are expecting!

Other extension types can be used to contain viruses too but the following are less common than the ones I mentioned above -

Picture files such as: JPG, PNG, BMP, GIF, TIFF, THUMB, PIC.

Documents which can be saved as: DOC, TXT, EX, RTF.

Movie file types which are typically: MPG, MPG4, MPEG, AVI, FLV, WMV.

The three different types of file extension that I mentioned above are less likely to be associated with malware but that doesn't mean they are always completely safe.

Whenever you receive a file you should exercise some basic security principles and apply a little bit of common sense before you open them.

Even if you receive files from a trusted source you should be a little wary and scan them with one of the top antivirus programs.