Rascals are always sociable, and the chief sign that a man has any nobility in his character is the little pleasure he takes in others company. Arthur Schopenhauer

Encrypted traffic interception on Hetzner and Linode targeting Russian XMPP messaging service

We have discovered XMPP (Jabber) instant messaging protocol encrypted TLS connection wiretapping (Man-in-the-Middle attack) of (aka service’s servers on Hetzner and Linode hosting providers in Germany.

The attacker has issued several new TLS certificates using Let’s Encrypt service which were used to hijack encrypted STARTTLS connections on port 5222 using transparent MiTM proxy. The attack was discovered due to expiration of one of the MiTM certificates, which haven’t been reissued.

There are no indications of the server breach or spoofing attacks on the network segment, quite the contrary: the traffic redirection has been configured on the hosting provider network.

The wiretapping may have lasted for up to 6 months overall (90 days confirmed). We believe this is lawful interception Hetzner and Linode were forced to setup. Encrypted traffic interception on Hetzner and Linode targeting the largest Russian XMPP (Jabber) messaging service