A trojan for Skype

Jake, phrases such as
> Skype, by its very nature, must use the network to send encrypted data to multiple untrusted machines elsewhere
and
> we don't really know what the Skype code does when it isn't infected
and
seem to suggest that there some sort of vulnerability in Skype. There isn't. The trojan will not automatically infect you over Skype; it is a normal Windows malware that relies on gullible users to ignore all warnings, download the file and install it (or on vulnerable web browsers to conveniently install the trojan without user interaction).