I am looking for some recommendations on how to secure the data of my physical servers (against physical theft), that I am about to set up. I am new to selfhosting but have a few years of experience running Linux on a desktop.
My usecase is a simple debian(?) server at home with Paperless ngx and Tailscale for when I am away from home.
The question is how to encrypt the data while still being able to keep the server updated.
Coming from Desktop my first thought was to simply enable FDE on install. But that would mean supplying the password everytime the server needs to reboot for an update. Could someone provide some insights on how often updates to debian require a reboot?
My second thought was to use an encrypted data partition. That way the server could reboot and I could use wireguard to ssh in and open the partition even when I am away from home for a longer time.
I am open to other ideas!
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Unless the crook happens to be extremely nerdy or its law enforcement, already being a Linux formatted partition feels it should be enough for a rando breaking in and stealing a computer.
That being said, something like a PiKVM connected to your server (and Tailscale) could let you enable both UEFI/boot password and propt for LUKS decryption upon boot.
I wouldn’t rely on the thief not knowing how to read linux partitions. That very well may be the case, but the person they sell your hardware to will know better, considering they are in the market of purchasing used server hardware.
I self host and my threat model is the thief selling my server to someone who knows what to do with it, but not knowing how to extract encryption keys from the memory of a running server before unpluging it. That being said I haven’t figured out encryption yet so watching this thread.
Somethign I haven’t seen mentioned yet is clevis and tang, basically if you have more than one server then they can unlock each other and if they’re spatially separated then it is very unlikely they get stolen at the same time.
Though you have to make sure it stops working when a server get stolen, using a mesh VPN works just as well after the server is stolen so either use public IPS and a VPN or use a hidden raspberry pi that is unlikely to be stolen or make the other server stop tang after the first one is stolen.
I’m using https://github.com/dracut-crypt-ssh/dracut-crypt-ssh on some of my servers. The initrd opens an ssh port where you can login and enter the passphrase. Setting it up is non-trivial, but it works well. Haven’t tried it on Debian but there should be something similar.
This is actually really interesting, I might have to try this.
I currently use a USB stick with a key file on it that I need to plug in on boot. Something like this but it wasn’t that easy for me. https://openterprise.it/2022/07/fedora-unlock-luks-full-disk-encrypted-system-using-usb-stick/
Edit: I wonder if yours will work on my VPS… I’d love to encrypt that.
You can use FDE and setup a minimal ssh server like dropbear to run at startup. This way, you can supply the password via a keyboard connected to the machine OR via ssh. This gives you a similar workflow to the data partition you mentioned, but encrypts the entire system.