I will be going through the malware in reverse chronological order, featuring the most current concerns first and the oldies but gnarlies last.
The first thing to know is that technically, ALL currently active Mac malware are Trojan horses. That means that they are entirely inert until such time as a user (or 'LUSER', in cynical terminology) inadvertently installs them.
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THE LIST:
1) Trojan.OSX.MACDefender.A - O [15 strains]
2) Trojan.OSX.BlackHoleRAT.A - C [3 strains]
3) Trojan.OSX.Boonana.A
4) Trojan.OSX.OpinionSpy.A - B [2 strains]
5) Trojan.OSX.iServices.A - C [3 strains]
6) Trojan.OSX.PokerStealer.A
7) Trojan.OSX.RSPlug.A - Q [17 strains]
The total number of Mac malware species are 7.
The total number of Mac malware strains are 42.
The 'Malware' Hacker Tools I Am Leaving Out:
'Trojan'.OSX.Lamzev.A
'Trojan'.OSX.Hellraiser.A - D [4 strains]
There are a number of inert malware as well as 'Proof of Concept' malware of no concern which I have also left out of my list. You may find them on other lists but you won't find them infecting anyone with up-to-date computers, apart for test computers in a lab. (A famous example of 'Proof of Concept' malware is Trojan.OSX.Oomp.A, aka Trojan.OSX.Leap.A. It is of no consequence or importance).
If you'd like a list of current 'legal' spyware, I suggest the list kindly provided at the MacScan/SecureMac site.
Note that, due to the lack of adherence to standards within the anti-malware community, there are a lot of name variations for the exact same malware. In the case of the MAC Defender Trojan I discovered 15 different names. I am not including them here in my list as these alternative names are irrelevant and needlessly confusing. What I have listed here are the 'official' names from my point of view as well as those whom I consider to be professional experts and original malware discoverers in the field. However, I will be listing a number of the alternative names in my subsequent articles that provide details about each of the current malware species.
As ever, I request corrections to my information. If I have missed a malware species or strain, please let me know asap. Much appreciated!