The Shylock banking Trojan has been revamped with extra features that allow the malware to spread using the chat function of Skype, the popular Voice over IP application.
Shylock can now roam the Skype network thanks to a new propagating plugin called "msg.gsm". This component also adds functionality including the ability to send messages and transfer files using Skype, the ability to bypass Skype warnings and restrictions as well as the facility to clean messages and transfers from Skype history.
Beside the new ability to spread through Skype, Shylock can also spread through local shares and removable drives. Infection by the Trojan allows cybercrooks to steal cookies, inject HTTP into a website, setup VNC (allowing remote control of compromised desktops), and upload files, among other functions.
read more...........http://www.theregister.co.uk/2013/01/17/shylock_trojan_skype/