Less than a week after researchers spotted new malware targeting naive Mac users, two additional titles have been spotted.

Security mavens at Mac anti-virus provider Intego say Trojan-horse software dubbed OSX.Trojan.iServices.B hitches a ride on pirated copies of Adobe Photoshop CS4 for Mac that are being distributed in warez channels. A program used to generate a valid serial number to unlock the Adobe app installs a backdoor on machines that makes them part of a botnet.

The discovery comes four days after Intego warned of a trojan that piggybacked off illicit copies of Apple's iWork 09 productivity suite.

The trojans aren't the only threats in the wild preying on OS X users. According to researchers at anti-virus provider Kaspersky, two new applications that claim to offer anti-malware protection for Mac users have recently been spotted. Rogue anti-virus programs have long been the bane of PC users. Now they're becoming increasingly common on the Mac platform as well, Kaspersky researcher Sergey Golovanov says.

No doubt, the debate about security of the Mac will continue to rage, with some claiming it is a harder platform to attack compared with Windows and others saying it remains relatively unscathed only because its considerably smaller market share makes it less of a target to cybercriminals. What should be fairly well settled is the reality that these Mac-tailored social engineering attacks are now a fact of life. Like their Windows brethren, OS X users who install pirated software or are otherwise careless do so at their own peril. ®