According to security firm, F-Secure, Bropia.C is a minor variant of Bropia.A, an IM worm identified last week. It spreads through MSN Messenger by sending itself as an IM message that reads "LOL.scr," "Webcam.pif," "hahahaha.pif," "me_2005.pif" or "sister.pif." Additionally, it copies a variant of the Rbot Trojan horse onto the machine. The Trojan horse opens a back door into Windows systems and can then log the keystrokes of the unsuspecting user, collecting system information and spreading Spim messages.