If you buy a Mac because you think they can’t be infected…

Think again:

Two pieces of malicious software affecting Apple’s Mac OS X appeared this week: a Trojan horse with the ability to download and install malicious code of an attacker’s choice, and a hacker tool for creating backdoors, according to security vendors.

The Trojan — called ‘OSX.RSPlug.D’ by Intego, the Mac security specialist that discovered the threat — is a variant on an older piece of malicious code but with a new installer, Intego said.

Naturally, it targets users in a traditional way:

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.

I find myself saying this a fair bit: Mac OS X is not necessarily more secure than any other OS. At the present time, given their lower market share, they’re just not as sweet a target as the Windows install base. As Macs reach a critical mass, they’ll become just as desirable to infect as any other computer.