I cannot find the packer of the executable

There is this executable that is packed however neither peid nor protection_id nor RDG tell me what it is, as they dont know.

How do i go开发者_如何学Go about finding the packer?

Or what if its' custom made?

It could easily have been derived from another packer in such a way as to destroy the signature by which the packer is recognized by those tools. Someone with experience looking at packed binaries might be able to detect obvious signs that it originated from a specific tool, but if all three tools fail to detect it, there's a good chances that it's custom made. A sign that it's custom made would be if the unpacking code is fairly simple and doesn't go through more than a few KB of code before executing the payload. Also look for signs that it doesn't look like it could pack generic program binaries.