DL3002

Last user should not be root.

Problematic code:

FROM busybox
USER root
RUN ...

Correct code:

FROM busybox
USER root
RUN ...
USER guest

Rationale:

Switching to the root USER opens up certain security risks if an attacker gets access to the container. In order to mitigate this, switch back to a non privileged user after running the commands you need as root.