And if reading / etc / passwd can in principle be described as an “innocuously enough” act, then why does Skype know everything about the Firefox profile, including the installed plugins, is not very clear. Perhaps checks whether the addon is installed for Skype in Firefox? Or trying to detect proxy settings? The official response from the developers yet. ')
For those who want to learn more about the protocol used by Skype, I also recommend reading the Skype article : The hidden threat on xakep.ru.