Trile is a worm that infects a large number of files on infected computers by copying itself to the beginning of them and ends active processes belonging to antivirus and security programs.

This worm mainly spreads via e-mail and the P2P (peer to peer) file sharing programs KaZaA and Shareaza. When it spreads via e-mail, Trile reaches computers in a message that includes an attached file with variable characteristics. However, this file always has a double extension:

• The first is one of the following: GIF, MPG, MP3, XLS, WAV, DAT, JPG, HTM, XLS, TXT, MDB, BMP, DOC or ZIP
• The second is PIF, BAT or SCR.

When it has infected a computer, Trile sends itself out to all the contacts in the Address Book in Outlook

Trile is difficult to recognize, as does not display any warnings or messages that indicate that it has infected a computer.