LUKS mermaids of remote unlock
Recently, I’ve browsed several how-to’s regarding the possibility of unlocking a LUKS root volume remotely using an SSH connection. For reference, the first of its kind is the one for Debian, published at Coulmann.de. Some of these how-to’s were posted to forums and mailing-lists and received many thankful comments from sysadmins wondering how to make their encrypted secure setup also easy to administrate.
The problem with their approach is simple: they asked how to fix their setup, but forgot to ask what they’re trying to protect. Having your root filesystem on an encrypted disk doesn’t protect you from remote exploitation or credential leaks. It just protects you from the risk of someone being able to access your machine locally and steal your data, or just steal the whole machine altogether. Now, if I were an attacker having access to your hardware locally,