|.EXE||An executable program file. Most of the applications running on Windows are .exe files.|
|.PIF||A program information file for MS-DOS programs. While .PIF files aren’t supposed to contain executable code, Windows will treat .PIFs the same as .EXE files if they contain executable code.|
|.APPLICATION||An application installer deployed with Microsoft’s ClickOnce technology.|
|.GADGET||A gadget file for the Windows desktop gadget technology introduced in Windows Vista.|
|.MSI||A Microsoft installer file. These install other applications on your computer, although applications can also be installed by .exe files.|
|.MSP||A Windows installer patch file. Used to patch applications deployed with .MSI files.|
|.COM||The original type of program used by MS-DOS.|
|.SCR||A Windows screen saver. Windows screen savers can contain executable code.|
|.HTA||An HTML application. Unlike HTML applications run in browsers, .HTA files are run as trusted applications without sandboxing.|
|.CPL||A Control Panel file. All of the utilities found in the Windows Control Panel are .CPL files.|
|.MSC||A Microsoft Management Console file. Applications such as the group policy editor and disk management tool are .MSC files.|
|.JAR||.JAR files contain executable Java code. If you have the Java runtime installed, .JAR files will be run as programs.|
.BAT – A batch file. Contains a list of commands that will be run on your computer if you open it. Originally used by MS-DOS.
.CMD – A batch file. Similar to .BAT, but this file extension was introduced in Windows NT.
.VB, .VBS – A VBScript file. Will execute its included VBScript code if you run it.
.VBE – An encrypted VBScript file. Similar to a VBScript file, but it’s not easy to tell what the file will actually do if you run it.
.WS, .WSF – A Windows Script file.
.WSC, .WSH – Windows Script Component and Windows Script Host control files. Used along with with Windows Script files.
.PS1, .PS1XML, .PS2, .PS2XML, .PSC1, .PSC2 – A Windows PowerShell script. Runs PowerShell commands in the order specified in the file.
.MSH, .MSH1, .MSH2, .MSHXML, .MSH1XML, .MSH2XML – A Monad script file. Monad was later renamed PowerShell.
.SCF – A Windows Explorer command file. Could pass potentially dangerous commands to Windows Explorer.
.LNK – A link to a program on your computer. A link file could potentially contain command-line attributes that do dangerous things, such as deleting files without asking.
.INF – A text file used by AutoRun. If run, this file could potentially launch dangerous applications it came with or pass dangerous options to programs included with Windows.
.DOC, .XLS, .PPT – Microsoft Word, Excel, and PowerPoint documents. These can contain malicious macro code.
.DOCM, .DOTM, .XLSM, .XLTM, .XLAM, .PPTM, .POTM, .PPAM, .PPSM, .SLDM – New file extensions introduced in Office 2007. The M at the end of the file extension indicates that the document contains Macros. For example, a .DOCX file contains no macros, while a .DOCM file can contain macros.
.REG – A Windows registry file. .REG files contain a list of registry entries that will be added or removed if you run them. A malicious .REG file could remove important information from your registry, replace it with junk data, or add malicious data.