I want to make well-known malicious programs, like
Incognito, undetectable by anti-virus solutions.
I have already tried various approaches myself, like packing the binary with UPX or modifying the source code in C/C++ (+ various compiler optimizations). Suffice it to say, that my source code modifications are not simple, but using various forms of refactoring and removal of unnecessary features.
However, while all my attempts have reduced the number of detections on virustotal.com, still the majority of anti-virus solutions flags the resulting binaries as malware.
How can I modify or obfuscate the programs, either at the source code or binary level, to make them undetectable by majority of anti-virus solutions?