What is Autorun.inf ?
Autorun.inf is a simple text-based configuration file present on the removable media that is associated with the Autorun function. It is a command script used to process the disk drives or Flash drives automatically as and when the removable media is inserted or connected into your system.
How does it Work?
Autorun.inf contains information for the operating system and instructs the OS from which file or application to start, which icon to display for the removable media, and which additional menu commands to offer. In other words, autorun.inf tells Windows how to open the file or application and treat the contents of these removable disks.
The whole process gets started when you connect a removable media to your system. As soon as you insert the device, the “Disk change notification” polling discovers a new disk on your PC and the “Auto insert notification” feature will be enabled (by default). Then your OS checks in root directory of the new disk for the presence of an “autorun.inf” file. If found; then Windows reads and follows the specific instructions that are defined by the file. If not found; Windows refers to the new disk by its serial number and performs the default actions that are associated with the content present on the disk (can be text, audio, video etc.).
Mainly, the Autorun.inf file defines:
- The process or application that will automatically run when a disk is inserted
- The icon represents your application's CD, DVD or any other removable media when the drive is viewed with My Computer or Explorer
- Menu commands that are displayed when the user right-clicks the media icon
Autorun.inf abuse
Autorun.inf can also be exploited in order to allow a malicious program to execute automatically without user knowledge. This autorun.inf file contains a “Shortcut” to certain executable files that should be executed after inserting a removable media (e.g. an USB stick). But, this mechanism is abused by some infections for automatic execution after inserting the media to any computer and hence, it is tuned as a virus at times. When this portable media is connected to your system, it spreads easily & occupies on your System directories.
Autorun.inf Deletion
You can safely delete this autorun.inf file from removable media. Before deleting first check the autorun.inf to which file it is pointing to. If it is directing to the already removed application (executable file), then just delete it else leave it. In order to check this, right-click on the autorun.inf file, select “Edit” from the menu items list. Find the referenced file name tab and check it for the file.
Now, to delete the autorun.inf just follow:
- Right-click on the respective drive and select the Browse menu item
- Make sure that hidden files are set to be displayed
- Locate and delete the autorun.inf file from the root folder on the drive
