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I see the ‘not a security boundary’ thing repeated constantly, and while it makes sense (eg. they’re sharing the underlying kernel or at least some access to it) if you think about it a little more, VMs are not magically different: they are better isolated, but VMs on the same host still share the host in common. A CVE next week that allows corruption of host state that affects eg every VM under a particular hypervisor will be no less damaging than this CVE is to containers

by throw0101c57 minutes ago|

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> […] VMs are not magically different: they are better isolated, but VMs on the same host still share the host in common.

VMs are not different due to 'magic' but through hardware assist with things like Intel VT-x and AMD-V:

* https://en.wikipedia.org/wiki/X86_virtualization#Hardware-as...

* https://blog.lyc8503.net/en/post/hypervisor-explore/

* https://binarydebt.wordpress.com/2018/10/14/intel-virtualisa...

by necovek5 hours ago|

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You are obviously right that these are similar in principle: VM isolation exploit would lead to the same exposure like container-related isolation exploits.

VMs are considered vastly better because the surface area where exploits can happen is smaller and/or better isolated within the kernel.

If you are arguing the latter is not true — and we are all collectively hand-waving away big chunk of the surface area so that may be the case — it would help to be explicit in why you believe an exploit in that area is similarly likely?

by robertlagrant3 hours ago|

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I would say it's the fact that "not a security boundary" appears to be a pass/fail statement, whereas the reality is more like a security continuum, along which VMs are further than containers.

by staticassertion1 hours ago|

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Containers are a security boundary, yes.

> A CVE next week that allows corruption of host state that affects eg every VM under a particular hypervisor will be no less damaging than this CVE is to containers

Yeah this almost never happens though whereas Linux privesc is 10x a day.

by graemep2 hours ago|

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They may not provide isolation as VMs but they clearly do limit some attacks. VMs do not provide the same isolation as using physically separate hardware either.

I would have thought they provide better isolation than using multiple users which is the traditional security boundary.

It might depends on what you mean by a container? Are sandboxes such as Bubblewrap and Firejail containers?

by ButlerianJihad6 hours ago|

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Containers are a convenience boundary and they increase complexity of your risk assessments.

It is easy for security scanners to scan a Linux system, but will they inspect your containers, and snaps, and flatpaks, and VMs? It is easy for DevOps to ssh into your Linux server, but can they also get logged in to each container, and do useful things? Your patches and all dependencies are up-to-date on your server, but those containers are still dragging around legacy dependencies, by design. Is your backup system aware of containers and capable of creating backup images or files, that are suitable for restoring back to service?

by necovek5 hours ago|

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Security scanners already support most container and VM image formats in widespread use.

Does this increase complexity? Yes, it does. Is it worth the cost? Depends on each individual case IMO.

by throw0101c45 minutes ago|

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> Security scanners already support most container and VM image formats in widespread use.

E.g.,

> Container Security stores and scans container images as the images are built, before production. It provides vulnerability and malware detection, along with continuous monitoring of container images. By integrating with the continuous integration and continuous deployment (CI/CD) systems that build container images, Container Security ensures every container reaching production is secure and compliant with enterprise policy.

* https://docs.tenable.com/enclave-security/container-security...

by firesteelrain4 hours ago|

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You need a tool like Anchore and PrismaCloud to scan the container images then monitor them in runtime with PrismaCloud. Trellix can “scan” however most people turn off or exclude container directories on the host because it can interfere with the running container.