If you’ve got Skype, you’ll want to know about the Trojan T9000. It’s malware that records your conversations, both video-calls and text messaging, and is virtually undetectable to security suites. And because it’s a Trojan, you won’t even know about it.
The T9000 Trojan provides backdoor access to your private information, automatically capturing encrypted messages, taking screenshots, recording audio files and documents sent via Skype. The problem appears to be a problem only on Windows, not on Macintosh.
The T9000 aims to capture monetary data, trade knowledge, intellectual property, and personal information including usernames and passwords.
You can read more about this security problem in an article by Philip Bates in the MakeUseOf web site at http://www.makeuseof.com/tag/trojan-malware-might-recording-skype-conversations/.
How can you avoid the problem? Philip Bates suggests not opening any Rich Text Format (RTF) files in your email inbox. I would think an easier and safer solution would be to simply stop using Skype. After all, there are several competitive products that are already known to be more secure than Skype anyway.
See my earlier articles at https://privacyblog.com/2015/01/13/nsa-documents-show-that-the-agency-can-grab-all-skype-traffic/, https://privacyblog.com/2016/02/08/now-in-pubic-beta-zyptonite-is-like-skype-only-much-more-private/, https://privacyblog.com/2014/11/24/tox-an-encrypted-skype-replacement/, and https://privacyblog.com/2015/01/23/megachat-a-browser-based-encrypted-voice-and-video-chat-app/.