Recently, I submitted 2 files to avast which I know are rogues. Before submitting, there was no detection from avast. But after submission and a VPS update, the rogues are detected as Win32:Trojan-gen.
So is it a generic/heuristic detection or a signature detection?
All those with -gen are generally (couldn’t help myself) generic. Heuristic detections tend to have a [Heur] suffix after them. Or in the case of anti-rootkit detections have it mentioned in the alert window, e.g. detection made using heuristic methods, or words to that effect.
Because the signature (generic) is designed to detect multiple variants of malware ‘trojans in this case.’ For a detection to be given a specific signature/name first a sample must be received/analysed, a signature and name produced and included in the next VPS.
This all takes time and the generic signatures serve an important purpose in detecting new variants that might otherwise not be detected.