Detekt scans for known commerical spyware like FinFisher and Hacking Team's RCS
Detekt currently detects FinFisher and Hacking Team's Remote Control System. Commercial surveillance spyware used by various governments and other creeps. Development is supported by the EFF and others.
Detekt is a rather simple tool and for now it just claims to detect the above mentioned spyware. Considering that the two are among the most wide spread tools it sounds less than it is for a tool like this. The tool seems to still have some problems with not detecting itself however. Browser caches and AV software that might copy the binary to scan it itself could trigger a false alarm. Something you should keep in mind if you want to test your system.
It's also very likely that the companies behind FinFisher and RCS will react to avoid detection in the future but it's not going to be as easy as it used to be. Some AV scanners have included this kind of spyware. Two month ago however only 6 managed to detect FinFisher and since this malware is used by governments there is a high risk that some might be forced to whitelist it.