Various exemplary embodiments relate to a method and related network node including one or more of the following: determining by the network device that an S9 session should be audited; determining that the S9 session is a suspect session; transmitting an S9 message to a partner device, wherein the S9 message includes an innocuous instruction; receiving, at the network device, a response message from the partner device; determining, based on the response message, whether the suspect session is orphaned; and if the suspect session is orphaned, removing an S9 session record associated with the suspect session.