Apple has long prided its OS on being virus-free, however, a new OS X trojan horse virus has been discovered called "OS X/Cointhief.A" that steals your Bitcoins.
This virus comes disguised as an app called StealthBit that users can use to send and receive Bitcoin Stealth Addresses, but instead secretly monitors all of your web traffic looking for Bitcoin-related logins and passwords.
Once installed, the tainted version of StealthBit installs browser extensions into Google Chrome or Safari (depending on what you use). The malicious browser add-ons then seek out login information for a multitude of Bitcoin services, including MtGox, Blockchain.com, and BTC-e. Once the iffy extensions locate your login information, it sends that data back to whomever developed the malware.
Already, users are being affected and a poster reported losing 20 Bitcoins, which is worth about US$14,000.