The session token protocol for forensics and traceback

Abstract

In this paper we present the Session Token Protocol (STOP), a new protocol that can assist in the forensic analysis of a computer involved in malicious network activity. It has been designed to help automate the process of tracing attackers who log on to a series of hosts to hide their identity. STOP utilizes the Identification Protocol infrastructure, improving both its capabilities and user privacy. On request, the STOP protocol saves user-level and application-level data associated with a particular TCP connection and returns a random token specifically related to that session. The saved data are not revealed to the requester unless the token is returned to the local administrator, who verifies the legitimacy of the need for the release of information. The protocol supports recursive traceback requests to gather information about the entire path of a connection. This allows an incident investigator to trace attackers to their home systems, but does not violate the privacy of normal users. This paper details the new protocol and presents implementation and performance results.