SSH Key Vulnerability

     A new ssh key vulnerability has been found affecting RSA keys which are the default in many older Linux implementations.  I strongly suggest generating a new ed25519 key using the command ssh-keygen -t ed25519 and remove any RSA keys you may be using. To do this remove relevant lines from your ~/,ssh/authorized_keys file. RSA keys will all start with ssh-rsa.

     Although any keys other than RSA will be safe from this particular attack, I recommend ed25519 because, being an elliptical curve algorithm, it is presently safe from all known quantum computer based attacks.  Any algorithm that depends upon the ability to factor the product of two large primes is vulnerable to quantum computers because they make this a very fast and easy task.

     After you make this new key and delete your old RSA keys you will need to use ssh-copy-id login@hostname to be able to use ssh-key authentication on that machine.

     Here is the article where I learned about this new exploit.  Unfortunately they don’t get into detail about what comprises a computational error, whether this is a hardware or an algorithmic error.