Expected
I've been wondering since the '90's when one would appear. Add polymorphism to the mix and wer'e off to the races.
Hackers have developed a a cross-platform backdoor capable of infecting Windows, Linux or Mac OS X desktop computers. The Mokes malware family is able to steal various types of data from the victim’s machine, including but not limited to screenshots, files and keystrokes. Researchers at Kaspersky Lab first came across …
It'll be interesting to see what the vector is (if they find any, otherwise we have to assume infected binaries). The Mac may be fairly resistant to drive-by virus infections but there too are we slowly training people to ignore admin right warnings.
LibreOffice, for instance, only signs the US variant, but not the language packs. Every time they update there's a user risk.