Hi all,

as I’m running a lot of docker containers in my “self-hosted cloud”, I’m also a little bit worried about getting malicious docker containers at some points. And I’m not a dev, so very limited capabilities to inspect the source code myself.

Not every docker container is a “nextcloud” image with hundred of active contributors and many eyes looking at the source code. Many Self-Hosted projects are quite small, and Github accounts can be hacked, etc. …

What I’m doing in the moment, is:

Project selection:
- only select docker projects with high community activity on GitHub and a good track record

Docker networks:
- use separate isolated networks for every container without internet access
- if certain APIs need internet access (e.g. Geolocation data), I use an NGINX-proxy to forward this domain only (e.g. self-made outgoing application firewall)

Multiple LXC containers:
- I split my docker containers into multiple LXC instances via Proxmox, some senitive containers like Bitwarden are running on their own LXC instance

Watchtower:
- no automatic updates, but manual updates once per month and testing afterwards

Any other tips? Or am I worrying too much? ;)

  • jesuisoz@alien.topBEnglish
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    11 months ago

    You’re not worrying too much. Projects selection, global awareness is definitely the crucial point.

    Isolated networks and concerns is also important.

    To avoid data leak, take time to review your firewall rules. Do not “allow to any” from LAN interface. Take time to allow just the ports you need. It takes time and everyone at home is going to scream when using a new app/software, but it’s worth the price.

    You can also add IDS/IPS on the lan side to prevent malicious app establishing outside connections. Have a look at ZenArmor or Crowdsec.

    You can also have a look at proxmox internal firewall system to isolate VM and their accessibility scope.

  • ck_@discuss.tchncs.deEnglish
    0·
    11 months ago

    You are not worried too much.

    Docker containers are notoriously riddled with outdated, security issue loaded content. Even reputable creators (eg. Nextcloud) only really bother with their own part of the container, but rarely release new builds of their containers when system dependencies could get updated, even less so for base images they depend on. So yes, Docker containers should always be run in a very secure environment, and doing so is by no means trivial, given that docker itself runs as root. Best advice, if you can: don’t run Docker containers if you don’t really have to, don’t run docker containers if you are not sure what you are getting into.

  • nukacola2022@alien.topBEnglish
    0·
    11 months ago

    Since you are using LXC/LXD, make sure that AppArmor is enabled on the host and ensure that a configuration profile exists (should be a decent default one available) that blocks the containers from reading things like the /etc/passwd file.

    I personally run all containers in centos/alma/fedora systems specifically to take advantage of the strong SELinux-container policies.

    Other things you can do would be to rebuild public images, patch them, and save them to your private registry. I find that not all container maintainers patch as aggressively as I would like. Furthermore, you can look into running containers as non root and use a non root “daemon” like Podman instead of Docker.