AttachMsngr.G is a Trojan that steals all type of information about the user, such as passwords and usernames, by logging the keystrokes typed by the user and all the movements made with the mouse.
Additionally, it is designed to store a log with the user's MSN Messenger conversations, possibly with malicious purposes.
Then, all the harvested information is sent to its creator via email. In order to do so, it uses its own SMTP engine.
AttachMsngr.G does not spread automatically using its own means. It needs an attacking user's intervention in order to reach the affected computer. The means of transmission used include, among others, floppy disks, CD-ROMs, email messages with attached files, Internet downloads, FTP, IRC channels, peer-to-peer (P2P) file sharing networks, etc.