Recently I suddently couldn't log into Openvas v8 running on Ubuntu 14.04 anymore. Nothing had changed about the machine (as far as I knew), but I got the following message when trying to log in with any account:
Login failed. OMP service is down
The logs (/var/log/openvas/openvasmd.log) showed the following message:
lib serv:WARNING:2016-01-19 15h52.12 utc:21760: Failed to shake hands with peer: The signature algorithm is not supported. lib serv:WARNING:2016-01-19 15h52.22 utc:21775: Failed to shake hands with peer: A TLS packet with unexpected length was received. md main:CRITICAL:2016-01-19 15h52.22 utc:21775: serve_client: failed to attach client session to socket 12 lib serv:WARNING:2016-01-19 15h52.22 utc:21775: Failed to gnutls_bye: GnuTLS internal error. lib auth: INFO:2016-01-19 15h53.56 utc:25472: Authentication configuration not found.
Turns out the libgnutls library was updated and it turned off support for downgrading signature algorithms.
If you got your Openvas installation from the Mrazavi Launchpad source, you can fix the problem by simply updating and upgrading:
sudo apt-get update && sudo apt-get upgrade