Anyone who uses Skype has consented to the company reading everything they write. The H‘s associates in Germany at heise Security have now discovered that the Microsoft subsidiary does in fact make use of this privilege in practice. Shortly after sending HTTPS URLs over the instant messaging service, those URLs receive an unannounced visit from Microsoft HQ in Redmond.
A reader informed heise Security that he had observed some unusual network traffic following a Skype instant messaging conversation. The server indicated a potential replay attack. It turned out that an IP address which traced back to Microsoft had accessed the HTTPS URLs previously transmitted over Skype. Heise Security then reproduced the events by sending two test HTTPS URLs, one containing login information and one pointing to a private cloud-based file-sharing service. A few hours after their Skype messages, they observed the following in the server log:
126.96.36.199 - - [30/Apr/2013:19:28:32 +0200] "HEAD /.../login.html?user=tbtest&password=geheim HTTP/1.1"