One of the benefits of Skype’s P2P nature and propriety encrypted communications system was that snoops had some trouble listening in on what you were saying. 

Ruben Unteregger, a Swiss programmer formerly working for a company allegedly developing government sponsored spyware, released source code for a trojan late last week that he claims allows hackers to “...intercept all audio data coming and going to the Skype process,” shattering any notions that Skype conversations are secure. 

The trojan in question records calls on an infected PC before they\'re encrypted and sends the recorded MP3\'s to distributors of the Trojan.

Unteregger explained in an interview with German portal Gulli.com that he made available the source code under the GPL license so as to weaken the efficiency of the trojan. He said that, “the code will be published, it will get analysed as soon as the binaries got uploaded, signature patterns will be created by antivirus companies, the malware will be detected, blocked and deleted, if it tries to infect a system.” 

“What we\'re looking at is something that could be considered the first ‘wiretap Trojan,” noted a Symantec blog post on Thursday, 27 August. The good news is that this is largely a proof-of-concept threat and not something that is affecting Skype users at present.