Srikanth Sundaresan, Damon McCoy, Sadia Afroz, and Vern Paxson
Online underground forums serve a key role in facilitating information exchange and commerce between gray market or even cybercriminal actors. In order to streamline
bilateral communication to complete sales, merchants often publicly post their IM contact details, such as their Skype handle. Merchants that publicly post their Skype handle
potentially leak information, since Skype has a known protocol flaw that reveals the IP address(es) of a user when they are online.