I feel super dumb right now.
I always thought, that all user data (/home/) are decently safe against physical access, as long as my user and root password is strong enough. If I just plug in the hard drive, nobody except the Super User has access to the data on it.
Well, the guys on the other community (Link) have shown me how wrong I’ve been.
All of my devices are securely encrypted. Well, all of them, except the most important one: my server, where all pictures, documents and other private stuff is stored.
Now, I’m afraid as hell that this will go wrong in the future.
Imagine a vengeful ex girlfriend, a police raid, whatever.
It’s just dumb from my side to secure everything except the one thing that would need it the most.
I’ve already done my homework, and encryption doesn’t seem like a highly important topic in the selfhosting community, or on many servers else.
At least that’s what I’ve got the feeling.
The most common argument I hear is “nobody will get physical access anyway, so I don’t care”.
Threat model and security measures
My threat model: not high. I don’t do any illegal stuff and don’t have any enemies. Still, I want everything at least somewhat secure.
If it only serves the purpose to annoy the intruder it’s already enough.
The only thing that has online access is my Nextcloud (AIO from Docker), and that is already well secured against hacking attacks (password, 2FA, brute force protection, etc.).
It’s also the only thing that is worth securing in my eyes.
Options for encryption
LUKS2 full disk
I would need to factory reset the whole server for that, which would be … highly inconvenient for me. It took me quite a long time to get everything working, and I don’t wanna loose my configuration.
Also, how should I access the device when I don’t see anything? Is there a workaround or something when I want to reboot without a monitor and keyboard?
Only encrypt the home folder
Same problem as with FDE
Nextcloud server side encryption
That one isn’t recommended from what I’ve read. It causes compatibility issues and an extreme hit on performance according to forums. Is this still correct?
Cryptomator (?)
Encrypting and decrypting with every up- and download sounds quite annoying. Wouldn’t be my prefered method tbh.
What is your opinion on that topic? What would you recommend me?
Please remember, that I’m not that experienced as much, so please be patient with me 😬
I would need to factory reset the whole server for that, which would be … highly inconvenient for me. It took me quite a long time to get everything working, and I don’t wanna loose my configuration.
This is your actual problem you need to solve. Reinstalling your server should be as convenient as installing a basic OS and running a configuration script. It needs to be reproducible and documented, not some mystery black box of subtle configurations you’ve forgotten about ages ago. A nice, idempotent configuration script is both convenient and a self-documenting system for tracking all the changes you’ve ever implemented on your server.
Once you can do that, adding whatever encryption you want is just a matter of finding the right sequence of commands, testing it (in another docker perhaps) and then running your configuration script to migrate your server into the desired state.
Any chance you can share some examples of the kinds of configuration script you’re thinking of, and best practices for creating one in the first place / maintaining it as you make changes to your system?
I would say there are better methods to solve this problem these days than a script. Check out Ansible or NixOS.
https://xsrv.readthedocs.io/ (or plain ansible)
I absolutely agree with this. If you cannot easily reproduce you configuration, all you are doing is pushing the problems down the line. Eventually, even simple things will get uncomfortable because it becomes uncomfortable to make. Better address the problem now while its still small
You can use cryptsetup-reencrypt to encrypt an existing disk in place with LUKS. Then you just have to modify the initramfs/bootloader/fstab to point to the new configuration. See https://wiki.archlinux.org/title/Dm-crypt/Device_encryption#Encrypt_an_existing_unencrypted_file_system
If that’s not possible or desirable for whatever reason like not having other drives to backup the data to, there’s some more options: if it’s ext4 there’s fscrypt which you can then just move the files to the encrypted folder, otherwise there’s gocryptfs. In both cases you only need enough free space for a temporary copy of the biggest file.
Encrypting your disk only provides at-rest protection, meaning there are entire swathes of physical attacks it provides zero protection against. Tons of stuff a malicious actor can do during runtime with physical access that you’d never notice. it quite literally only protects against thugs smashing your door in and physically walking away with the disk.
So if you’ve painted yourself into a corner with a baby’s first config, what you can do to step up your level of data protection (until you can redo your setup properly) is creating an encrypted filesystem or filesystem image (use fallocate to create a large empty file, then connect it to a loopback device, encrypt with LUKS, and use it as a virtual filesystem), rsync your data directory to it, and then unlock/mount it at boot under the directory where Nextcloud is configured to store your data. It’s god-awful, but this should be more or less transparent to Nextcloud if you do it right, and then at least your data directory gets at-rest encryption, and tbqh if someone is smash and grabbing your hard drive they are probably more interested in your data than they are your OS config.
I wouldn’t say this is an acceptable or preferable alternative to FDE, but it sounds like you’re still figuring out the best ways to set these things up, and this will get you more protection than none. But, realistically, you should probably not worry about it too much and should think about the security of your setup as a learning exercise/study in best practices.
Luks full disk encryption and encrypted offsite backups. This protects from most common smash and grab scenario.
I had issues where system upgrades would loose encryption keys and full restore from backup was my only option. Nextcloud have issues with encryption, some features are not available if you enable it (don’t remember which ones now).
Generally speaking if someone has physical access to your system you’re screwed. There are many ways that physical access can be used to get access to your data including denying you access to your data.
Full disk encryption. It wnt do anything if the server is powered on and they plug in a flash drive, but if it were to have the physical disks taken out or the server is powered down and moved.
Disable removable media. Might be able to do it in the bios, but I’d not, you should be able to in the OS.
Easiest one though is to lock the door to the room. Or to the rack if you have it in a rack.
I understand a complete server reset would be inconvenient.
I’m quite fond of veracrypt: It offers good encryption and is transparent when mounted.
You can create and mount a container file with veracrypt, copy your existing data in there and replace the original folders with appropriate symlinks. I think thats the best tradeoff for good protection and convenience
A shotgun. It really is the answer.
Edit: I’ve had people break into my house wearing bullet proof vest… And they weren’t cops. So aim for the head.
Even if firearms were legal in my country, I wouldn’t murder someone because of some embarrassing photos where I discovered Snapchat filters when I was 15.
Also, if they were legal, they wouldn’t help, since I’m not 24/7 at home
…
