I stumbled upon a thread on another forum about making external hacks undetected even if previously detected and I wanted to confirm that what they're saying is actually right or not.
'this tutorial is about making your external hack a protected process, effectively guarding it from everything in your system which is user-mode.
the main drawback was that you'll need kernel-mode access yourself to promote the process to a protected process, which can be accomplished with a driver. however in a 64bit windows this driver has to be signed or you'd have to run windows in "testsigning" mode or even disable signature checking for drivers completely. so i thought: why not simply use CheatEngine for the job, since it comes with a 32bit and a signed 64bit driver already, so you can use it "out of the box".' Also, something about changing your window title every time you make it undetected. It's a pretty good tutorial, I could follow it but it was posted back in January and i'm not sure if it's still working.
It's an extremely long tutorial that's a bit technical but that's about what it's about.