Let’s say you have access to a remote machine and use it to copy backups occasionally, eg with rsync. Your local machine has credentials stored that allow write access on the remote machine, however if the local account was compromised that could also allow access to the remote machine and the data stored there.
How can you grant access to an account to write remotely, but also protect the data from this account? One possibility could be to change the permissions on the data after it is copied to prevent deletion/interference, although I’m just making this up. Is there a standard practise for this?
OP asked:
So I was thinking that the account should not be able to delete the filesystem in an unrecoverable way. Like overriding the current fs with random data or an encrypted fs and filling it etc.
Like I said on a Hetzner storage box, multiple users get access to the same system, but each one only has file editing commands, not fs editing and they can only access their assigned directory. So if the system does scheduled snapshots (outside of that user’s scope of access) there is no way for a user to delete the files beyond recoverability. (no matter if their own files or other users files).
The user can still delete their own data. But because the fs is cow with snapshots (like btrfs) and they can not touch that, the data can be recovered easily.