50+ File Extensions That Are Potentially Dangerous on Windows

.exe files are not the only types of file extensions that may be potential harmful to your windows operating system. There are other file extensions you must be aware of as a user so as to protect your files.

Importance of knowing the threat posed by a file type

A lot of times you receive an email with a file attached or download a file from the internet not knowing if it will harm your operating system or not. By knowing the threat you are exposing your machine to, you will be able to exercise caution when handling these potential harmful files. Once you realize a certain file could damage your system the advisable thing to do is to immediately scan the file using an anti-virus to determine if it contains viruses or malware. Other online virus, malware and URL scanners such as VirusTotal will allow you to upload such a file to establish its threat. It’s not enough to have an anti-virus software running in the background of your computer, you need to know all the types of files that pose a threat to it.

The threat associated with file extensions

Not all file types are harmful but the threat is in the fact that they may contain malicious and damaging software, caution should therefore be exercised when opening these files as they may contain code or execute arbitrary commands.
Potentially dangerous file extensions are those that can run code such as .EXE, .SCR, .PIF, .HTA, .CPL among others. Others such as .JPEG AND .MP3 do not contain code thus are not dangerous. It is therefore important to know the kind of files that may contain codes, macros and other things that may put your operating system at risk.

Program file extensions

.EXE- It is an executable program file. Applications running on windows operating system are mostly of the .exe type.

.PIF-It’s a program information file for MS-DOS programs. Although it does not contain any executable code, PIFs are analyzed the same way as .COMS and .EXE by the shellexecute function and will thus run accordingly to their content and not the extension meaning they can be used to transmit viruses.

.MSI- It is an installer package file format used by windows. MSI files are used for installation, storage and removal of programs.

.APPLICATION- It is an application installer that is deployed with ClinkOnce technology in Microsoft

.GADGET- It was introduced in windows vista as a gadget file for the windows desktop gadget technology.

.MSP- It’s a Microsoft installer patch file that works hand in hand with .MSI files

.COM- It’s a simple executable file, the original type of program used by MS-DOS

.SCR- It’s a screen saver file for windows stored typically in the main windows directory. Screen savers are executable files that run when opened.

.HTA- It’s a Microsoft windows program whose source code consists of HTML, dynamic HTML and other scripting languages supported by internet explorer.

.CPL- It is a control panel file.

.MSC- Stands for a Microsoft management console file. An example of an application using this extension is the disk management tool.

.JAR- These types of files contain executable java code.


Scripts types

.BAT- It is a batch file, a kind of script file that consists a series of commands to be executed by the command line interpreter, stored in a plain text file.

.CMD- It’s a batch file similar to .BAT but was introduced in Windows NT.

.VB, .VBS- This type of files executes its included VB script code when run.

.VBE- It is similar to a VBScript file but an encrypted one.

.JS- This is a JavaScript file used mainly to run client end JavaScript commands on a webpage.

.JSE- This is a JavaScript Encoded file.

.WS, .WSF- A window Script file used by the Microsoft Windows Script host.

.WSC, .WSH- They stand for windows script component and windows script host control files respectively all part of windows script files.
Other script files are windows PowerShell script such as .PS1, .PS1XML, .PS2, .PS2XML, .PSC1, .PSC2 used to run PowerShell commands in the specified order and Monad Script file such as .MSH, .MSH1, .MSH2, .MSHXML, .MSH1XML and .MSH2XML.


.SCF-It is a Windows Explorer command file, command used by windows explorer like to move up or down a directory or show the desktop.
.LNK- Is a file extension for a shortcut file used by Windows to point to an executable file. It could potentially contain command attributes that may automatically delete your computer files.
.INF – This file is used by Auto Run meaning it could potentially run harmful applications it comes with.

Other files

.REG- This means it is a Windows Registry file that contains registry entries to be removed or added when you run it. Important registry information could therefore be easily replaced with malicious data if a malicious .REG file is run.

Files containing Macros

.PPT, .DOC, and .XLS mean they are Microsoft PowerPoint, Microsoft Word and Microsoft Excel respectively. These types of files could contain malicious macro code.
Other file extensions like .DOCM, .DOTM, .XLTM, .XLAM, .PPTM, .POTM, .PPAM, .PPSM and .SLDM are new files introduced in Microsoft office 2007. The presence of the M at the end of each file extension means the document contains macros.