[eqvinox]

It is technically never possible to guarantee tell-tale signs of an RCE. At the point where you're running compromised code, that code could in most cases be constructed as to erase its own tracks. There might be some visible sign at the moment of exploitation, but after that it's kinda over.

(Yes this assumes the RCE escalates to a reasonably high privilege, but that's just a matter of chaining. You can try to go for things like sealed logs, but ultimately arbitrary code can put your machine in an arbitrary state.)

Particularly insidious for this would be the case of data theft. The RCE might load some code to upload your company secrets and keep itself strictly in RAM, and then erase itself when done. With enough blackhat craftiness you'd never be able to pinpoint the exact location of the leak.