Mal/AutoInf-A is a malicious file usually found on USB drives or other removable storage devices. Mal/AutoInf-A automatically runs other malware when the infected device is connected to a computer running Windows.
Mal/AutoInf-A is commonly used by worms for the Windows platform as they spread from one computer to another.
A typical infection process is as follows:
1 - The worm copies itself to a removable storage device.
2 - The worm creates a copy of Mal/AutoInf-A on the device, usually in a file named autorun.inf.
3 - When the device is connected to an uninfected computer Mal/AutoInf-A activates the worm automatically.