I was speaking to some people from Vicomsoft the other day and they told me something interesting:
If you are using Skype you have a massive backdoor wide open to your computer, and since Skype data is encrypted it can fly through your firewall, in both directions...
They also mentioned that Skype uses the same peer-to-peer technology as Napster did. It's the same people.
The Vicomsoft people told me to take a look at a Skype report from the EADS Corporate Research Center security lab.
The report explains that Skype is a P2P VoIP software that can bypass firewalls and NAT to connect to the Skype network. This suggests that an attacker could send a packet to you that would enable him to gain full control of your computer.
I guess this might be more of a threat to PCs, but I'm not sure I'd want an open door on my Mac.
The EADS report was published in October 2005 and the flaw uncovered was subsequently fixed by Skype, according to this security advisory
It seems the security issue was solved at the time, but it does make me wonder why nothing more has been made of this open door to our computers. Are we really safe? Is someone somewhere hiding something?