[wahern]

If you're using a container as a sandbox, one should use a default deny policy and allow only the facilities required by the container. Though, in practice containers are used to package a huge collection of software, most of which the container creator has no familiarity with and no ability to determine what runtime dependencies, beyond other package names, are required. This one of the reasons why containers, generally speaking, don't offer reliable security. If you can't or won't carefully design your components to sandbox themselves (e.g. by using seccomp and landlock with policies tailored to the specific component), like Chrome or various OpenBSD daemons, then it's far better to use VMs for isolation; and if you do design your components that way, containers are superfluous from a security perspective.