OSX.Trojan.iServices.B is what the malware is being called. It affects some copies of Adobe Photoshop that are being distributed through pirate software sites. According to Intego, "The actual Photoshop installer is clean, but the Trojan horse is found in a crack application that serializes the program."
The crack application installs a backdoor in the /var/tmp directory, copies an executable to /usr/bin/DivX and saves the root hash password in the file /var/root/.DivX, according to Intego. It then listens on a random TCP port and attemps to make repeated connections to two IP addresses. Intego concludes that the creator of the malware intends to be alerted through this method and may have the ability to connect to affected Macs and perform various actions remotely.
"The Trojan horse may also download additional components to an infected Mac," reads Intego's security alert.
Mac users concerned about this issue are advised to install and run security software to protect themselves. Obviously, the best idea remains to only acquire your software legitimately and through trusted sources.
This story, "Mac Trojan Horse Discovered in Pirated Photoshop" was originally published by Macworld.