Sure, it's simple. But you would have to be able to modify the container settings anyway. For all practical uses, and certainly in my case, you could just make it run a different image at that point. Or copy another executable into the container and run it. You're already privileged. Requiring you to be privileged to access the debug server means it's secure.

Until things around change and what was previously "a secure backdoor" becomes a "less secure backdoor". ;-)

One can read every second week about cases where some backdoor that was meant to be used "only for debugging" landed in the end product and became a security problem.

Actually I usually suspect malice when something like that is found once again, as "who the hell could be so stupid to deliver a product with a glaring backdoor". But maybe there is something to Hanlon's razor… :-D