Yeah this smells bad. Especially given the box is set up to not accept the exploit (1mb vs 12mb).
> For those who are saying that the nginx config is unfairly difficult, intention was just to replicate a fairly normal config that was more realistic than you'd get in a lab environment. If we get to 24 hr+ with no solves I'll see about making it easier. In the meantime, seems like you can perhaps mitigate PHP2Shell with the right nginx config, so that's pretty neat!
That's the default though