The instructions for the exploitation of the bug that allows it were found on Pastebin by the Skype-Open-Source blogger, who tested them and confirmed they were effective.
The preparation for the uncomplicated execution of the process requires the download of a modified version of the Skype VoIP software and the addition of a few registry keys to turn on the creation of a debug-log file.
Next, the snooper must move to add the target's contact name to Skype and click on the user to view his information card. The action will make the IP addresses appear in the log file, and can be used to discover the city and country where the user is based, as well as his ISP.
H-Online confirmed that the exploit works and that even when a user was logged in with multiple clients, the IP addresses for all the clients were visible.
Shortly after they also discovered a web service (skype-ip-finder.tk) that offers the Skype users' IP address information without the need to have a valid Skype account.
One must simply enter the target's Skype username, solve a CAPTCHA, and get the IP address.
According to Neowin.net, Microsoft has reacted to the news by saying that an investigation into the matter is ongoing.
"This is an ongoing, industry-wide issue faced by all peer-to-peer software companies. We are committed to the safety and security of our customers and we are takings measures to help protect them," stated Adrian Asher, director of product security for Skype.