They have been listening in on the encrypted traffic on the Jabber network for a few months now.

Information about the breach and what needs to be done to stop it.

Hetzner and Linode in Germany host the project server and the VPS environments that help it run. On October 20, 2023, an attack was made on the "Man in the Middle" servers that run the jabber.ru service (also called xmpp.ru). The attack was aimed at the XMPP (Jabber) encrypted intercepting protocol of the TLS connections. They changed the TLS certificate on a transit node and sent traffic to it in order to get into XMPP connections that used the STARTTLS extension.

A unique SSL certificate was used to set up a proxy connection to TCP:5222 by attackers who haven't been caught yet. It was easy for us to find the attack because the bad guys messed up and didn't update the TLS certificate. The user who runs jabber.ru couldn't connect to the service because the certificate had run out.

On April 18, 2023, the fake TLS certificate was bought from the Let's Encrypt service. Chats on jabber.ru and xmpp.ru can be read by bad people. At first, people were worried that someone would break into the project server, but there was no proof of this in the audit.

The new part worked on both the Hetzner network and the Linode network as it turned out. Three hosts were used to change the path of Port 5222 traffic from two different service providers. This made it seem like the attack could have been planned by someone who was already on the network of the service provider.

Certificate replacement stopped after going to court and talking to the provider's support services. Some people on the project team believe that service providers who work for the German police or intelligence services may have known about the attack and helped bring it about.

If you use jabber.ru, you should change your passwords and look at your OMEMO and PGP keys to make sure they haven't been stolen.

The messages you send and receive during that time should all be thought of as possibly being harmful. Someone could read and even change messages in real time because the server did not encrypt them. It is only safe to talk on OMEMO, OTR, or PGP if both people agree on the encryption keys.