Open DAT File

Dangerous File Extensions

When user double clicks on a file computer decides what to do with it based on file extension associated with a file. If a file extension of a file is associated with an application, then computer will try to open the file using that application. That’s one of the reasons why certain file extensions could be dangerous. A file in question may contain some malicious data which causes an application to malfunction and do a damage to a computer or infect other computers. For example, if you open XLSX (Microsoft Excel) file which contains a malicious macro, Microsoft Excel will execute that macro which will cause the virus to spread. Even worse there is a type of file called executable which is executed by an operating system when you run it. If executable file contains malicious code it can do a significant damage to user’s computer.

Below are some of the most common extensions which are dangerous to user computer:

• XLSX, PPTX, DOCX, XLS, PPT, DOC – Microsoft office files may contain macro viruses. When such macro is executed it will infect other computers by sending e-mails to user’s contacts from Microsoft Outlook. Also, it may corrupt files on user’s computer.
• EXE, DLL, COM – Executable file extensions. Files with such extensions may contain viruses. When executed virus inside the executable file will gain full control of user’s computer.
• SH, VBS, BAT, CMD – Shell scripts extensions. When launched execute a sequence of a commands. May contain malicious commands.
• DMG, MSI – Used by Mac OS and Windows OS to install software. If downloaded from internet may install malicious software on a user’s computer
• APK – Android installation package. If downloaded from internet may contain mobile application with a virus or data collection code

In general, we recommend not to open files download from the internet or e-mail without a virus scan. Even good sites may get hacked and not notice that software package for download was infected with a virus. Many modern anti-virus packages have a real-time scan feature when they scan a file which is being launched. Having such anti-virus installed may prevent most of the threats from dangerous file extensions.

In most cases DAT file extension is not dangerous since it could not be opened directly when you double click on it. At the same time there are cases when malicious data may be stored in DAT file. A good example of it is winmail.dat file which is generated by Microsoft Outlook and stores rich formatting and attachments of e-mail. One of attachments in winmail.dat file may be an infected executable and it may infect user computer when attachment is opened.