Expert system assessing threat level of attacks on a hybrid SSH honeynet

摘要

Currently, many systems connected to the internet are exposed to hundreds of mostly automated network attacks on a daily basis. These are mostly very simple attacks originating from botnets. However, sophisticated attacks conducted both by automated systems and directly by humans are becoming more common. In order to develop adequate countermeasures, the behaviour of attackers has to be analysed effectively. Honeypots, a sort of lures for the attacks, are used for that purpose. Configuration of honey-pots vary depending on the type of attacks they focus on attracting. For simple, analogous attacks that sequentially repeat predefined commands, medium interaction honeypots are sufficient, while more sophisticated attacks require the use of high interactive honeypots. An essential part of the analysis is to differentiate between these types of attacks to make the overall analysis efficient, in terms of efficient use of hardware resources, and effective by providing the attacker with an appropriately emulated environment. This article first analyses the current situation followed by presenting a solution in the form of a system made up of a hybrid honeynet and an expert system. For now, it focuses only on the SSH protocol, as it is widely used for remote system access and is a popular target of attacks. The system has been tested on real data collected over a one-year period. The article also deals with making redirecting SSH connections as transparent as possible.