Dung.A is a worm that remains waiting to receive instructions, such as obtaining information about the affected system and connects to a certain website in order to download a malicious file.

Dung.A reaches the computer in a file that has the icon belonging to a Windows folder. It spreads via the instant messaging program Yahoo Messenger and through removable and mapped drives, making copies of itself in them.

Technical details can be found at this Panda Software page.