First Linux Mint, and now Transmission. Transmission (an opensource bittorrent client), specifically the MAC release of version 2.90 was found to contain ransomware named "KeRanger". The official site currently has a warning message up, the infected download has been removed, and a new safe download version 2.92 is being provided. However, there seems to be no information on how the download was compromised in the first place (perhaps they don't know yet?). Seeing as Tranmission is also available for Linux, I thought I'd mention it here, though presumably Linux is unaffected since they are only warning OSX users. Personally, I wouldn't download anything directly from their site until they've had a bit more time to sort things out.