An INF file (stands for information) or Setup Information file, is a plain text file used by Microsoft Windows for installation of software and drivers. INF files are most commonly used for installing device drivers for hardware components. Windows includes IExpress.exe for the creation of INF-based installations. INF files are part of the Windows Setup API.
The structure of an INF file is very similar to that of an INI file; it contains various sections that specify the files to be copied, changes to the registry, etc. All INF files contain a [version] section with a Signature value specifying the version of Windows that the INF file is meant for. The signature is commonly $CHICAGO$ (for Windows 9x) or $WINDOWS NT$ (for Windows NT/2K/XP) Most of the remaining sections are user-defined and contain information specific to the component being installed. An example of a INF file might have something like this:
[autorun] open=program.exe
What this would do is open the program.exe file automatically whenever the media containing the file (in its root directory) is connected to the computer. This can be dangerous, as there is no way to tell whether such a file exists before inserting the media. Since Windows XP, however, this feature has been replaced with a menu forcing the user to choose which action to take.
INF Files can sometimes be dangerous on Windows 2000 as they may allow viruses to autorun without prompting.
[autorun] open=program.exe icon=cd.ico
'icon=*.ico' command replaces any old/default drive icon with the specified one. [autorun] can be replaced by [AutoRun] or [Autorun].