Can a virus be detected by a signature that is of the same infection type even if there is no signature for that specific virus?
Is there any news as to if Avast will incorporate Heuristics for unknown viruses/malware in future as products like Norton provide it and have the ability to turn it up or down in sensitivity? (I would rather have false positives than not notice I’m infected)
If there is no signature on a signature base AV then no it can’t be detected.
There are a number of generic signatures that try to detect more than one virus/family so it may in this case detect a new variant if a significant part matches the generic signature. This can on occasion result in the detection of something that isn’t detected (an FP).
So avast uses generic signatures and by all accounts in version 5 will incorporate other methods (not released in any detail), but that isn’t heuristics as that definition is quite specific. Extreme care has to be taken with the introduction of something like heuristics as it can result in a large rise in FPs if not done correctly.