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Exactly! This is a huge pet peeve of mine. I feel like I'm going crazy when I read articles like this one (that is, any of the similar "how to escape containers

Exactly! This is a huge pet peeve of mine. I feel like I'm going crazy when I read articles like this one (that is, any of the similar "how to escape containers" blog posts). With the exception of a rare few that actually describe 0-days, the overwhelming majority seem to be exactly like this. It confuses the heck out of me because red-team-type people will shout from the mountaintops about how insecure containers are and how absolutely trivial it is to break out of them, but when I go look for an example of that trivialness, all I find is stuff like this. Not that these aren't at all useful techniques - there are plenty of containers with --privileged, or a Docker socket mount, etc. But surely this doesn't apply to >90% of containers out there, especially ones that are exposed to the Internet. Your average Redis or Nginx container, or some container running a Python or Node webapp, is not going to have Docker mounted or some weird capability added. Sure, misconfigs happen, us sysadmins get lazy, but this is really common-sense stuff. It feels almost unfair to "blame" it on the container. Of course, as mentioned, there are 0-days that allow for container breakout, and those are the truly scary stuff. But they seem to be few and far between, and they get publicized semi-widely and patched pretty quickly when they are found. So to this day I don't really understand all the security folks who act like they (as in any decent attacker, not just a nation-state with 0days up the wazoo) could break out of a container with their eyes closed, while the only material I can find on the open Internet is stuff like this. Am I just looking in the wrong places?

achierius 3y ago
But these caps aren't extraordinary — in particular I find often that using profilers and the like often requires them. E.g. the manual for Nvidia Nsight specifically tells you to add SYS_ADMIN, which as we see here breaks the seal. Ergo we can _either_ be able to run those tools, _or_ have a safe containerized workflow: that dichotomy alone is useful enough to justify this article IMO
- ipdashc 3y ago
  That's fair! That's a good point, and I don't mean to invalidate those situations. A part of me still feels like that's somewhat separate from a "typical" scenario where you want to harden a container that's exposed to the outside world in some way; like I said, your average container running a webapp or whatever. Nvidia Insight seems to be a performance analysis tool, so I would hope nobody is running it with untrusted input or exposing it to the Internet. (Yes, I know someone out there totally is.) Similarly, it feels near-obvious to me that adding a privilege called "SYS_ADMIN" to a container will make it more or less equivalent to root on the host. It's not like Docker hides this info from people, last I checked it's explained pretty prominently. You're totally right overall, it still matters, it's just something about this framing that rubs me the wrong way.

achierius 3y ago

But these caps aren't extraordinary — in particular I find often that using profilers and the like often requires them. E.g. the manual for Nvidia Nsight specifically tells you to add SYS_ADMIN, which as we see here breaks the seal. Ergo we can _either_ be able to run those tools, _or_ have a safe containerized workflow: that dichotomy alone is useful enough to justify this article IMO

ipdashc 3y ago
That's fair! That's a good point, and I don't mean to invalidate those situations. A part of me still feels like that's somewhat separate from a "typical" scenario where you want to harden a container that's exposed to the outside world in some way; like I said, your average container running a webapp or whatever. Nvidia Insight seems to be a performance analysis tool, so I would hope nobody is running it with untrusted input or exposing it to the Internet. (Yes, I know someone out there totally is.) Similarly, it feels near-obvious to me that adding a privilege called "SYS_ADMIN" to a container will make it more or less equivalent to root on the host. It's not like Docker hides this info from people, last I checked it's explained pretty prominently. You're totally right overall, it still matters, it's just something about this framing that rubs me the wrong way.