Tell HN: Ubuntu 24.04 force enables password auth, need to disable differently

8 months ago

Just installed Ubuntu 24.04 from the server image (https://ubuntu.com/download/server) and was just bitten by this.

Disabling password auth in `/etc/ssh/sshd_config` does nothing.

    # To disable tunneled clear text passwords, change to no here!
    PasswordAuthentication no
    ^ This is a lie, setting it to "no" does nothing

You also need to delete /etc/ssh/sshd_config.d/50-cloud-init.conf which contains a single line:

    PasswordAuthentication yes

Other people complaining about the same thing:

[0] https://www.mikeberggren.com/deb-ssh-auth

[1] https://askubuntu.com/questions/1516262/why-is-50-cloud-init-conf-created

[2] https://askubuntu.com/a/435620

8 comments

samlinnfer

Reply
lathiat  8 months ago

You can still configure it to be key only, you just need to put your own override as a file in /etc/ssh/sshd_config.d/ rather than /etc/ssh/sshd_config.

The files are read in order, so your filename needs to sort after the 50-cloud-init.conf file. This would work: echo "PasswordAuthentication no" > /etc/ssh/sshd_config.d/60-password-auth.conf

  • samlinnfer  8 months ago

    It is first configuration that sticks.

    That is how include * sshd_config_d overrides all subsequent lines in sshd_config.

    So it would need to be 00-password-auth.conf for it to work.

jcrben  7 months ago

add `ssh_pwauth: false` if you can edit the cloud-init configuration - that's what I'm doing