Not as serious as it may seem, but the hackers do seem to be gaining some ground on OS X.
The Trojan is found on porn websites posing as a codec needed to play video files, a technique used to trick the user into downloading and installing it.
OSX.Lamzev.A is a hacker tool designed primarily to allow attackers to install backdoors in a user’s system, according to Intego. However, the company dismissed the tool as a serious threat because a potential hacker has to have physical access to a system to install the backdoor.
Mac OS X targeted by Trojan and backdoor tool | Tech News on ZDNet