Skype and The Bavarian 'Trojan in the Middle'
[Files] obtained by Wikileaks and also released by the political party Piraten, contains two scanned documents relating to activities of the Bavarian police, Ministry of Justice and the Prosecution office in intercepting encrypted data submitted via SSL or Skype via the internet.More here.
The first one, presenting a communication on splitting cost between Bavarian police and the prosecutors offices, the second one presenting the related offer for the software by a German company called Digitask.
The technology, in high-level explained in the offer of Digitask, works via a local installation of a malware on the clients computer.
The offer dating September 4th 2007, replies an inquiry by Bavarian officials on the possibility of Skype interception, introduces a basic description of the cryptographic workings of Skype, and concludes that new systems are needed to spy on Skype calls.
It continues to introduce the so-called Skype Capture Unit. In a nutshell: a malware installed on purpose on a target machine, intercepting Skype Voice and Chat. Another feature introduced is a recording proxy, that is not part of the offer, yet would allow for anonymous proxying of recorded information to a target recording station. Access to the recording station is possible via a multimedia streaming client, supposedly offering real-time interception.
Another part of the offer is an interception method for SSL based communication, working on the same principle of establishing a man-in-the-middle attack on the key material on the client machine. According to the offer this method is working for Internet Explorer and Firefox web browsers. Digitask also recommends using over-seas proxy servers to cover the tracks of all activities going on.