Traceback: A Forensic Tool for Distributed Systems

In spite of stringent security measures on the components of a distributed system and well-defined communication procedures between the nodes of the system, an exploit may be found that compromises a node, and may be propagated to other nodes. This paper describes an incident-response method to analyse an attack. The analysis is required to patch the vulnerabilities and may be helpful in finding and removing backdoors installed by the attacker. This analysis is done by logging all relevant information of each node in the system at regular intervals at a centralised store. The logs are compressed and sent in order to reduce network traffic and use lesser storage space. The state of the system is also stored at regular intervals. This information is presented by a replay tool in a lucid, comprehensible manner using a timeline. The timeline shows the saved system states (of each node in the distributed system) as something similar to checkpoints. The events and actions stored in the logs act on these states and this shows a replay of the events to the analyser. A time interval during which an attack that took place is suspected to have occurred can be analysed thoroughly using this tool.