Deceiving Attackers by Creating a Virtual Attack Surface

Abstract

Cyber attacks are typically preceded by a reconnaissance phase in which attackers aim at collecting valuable information about the target system, including network topology, service dependencies, operating systems, and unpatched vulnerabilities. Unfortunately, when system configurations are static, attackers will always be able, given enough time, to acquire accurate knowledge about the target system through a variety of tools—including operating system and service fingerprinting—and engineer effective exploits. To address this important problem, many techniques have been devised to dynamically change some aspects of a system’s configuration in order to introduce uncertainty for the attacker. In this chapter, we present a graph-based approach for manipulating the attacker’s view of a system’s attack surface, which addresses several limitations of existing techniques. To achieve this objective, we formalize the notions of system view and distance between views. We then define a principled approach to manipulating responses to attacker’s probes so as to induce an external view of the system that satisfies certain desirable properties. In particular, we propose efficient algorithmic solutions to two classes of problems, namely (1) inducing an external view that is at a minimum distance from the internal view, while minimizing the cost for the defender; (2) inducing an external view that maximizes the distance from the internal view, given an upper bound on the cost for the defender. In order to demonstrate practical applicability of the proposed approach, we present deception-based techniques for defeating an attacker’s effort to fingerprint operating systems and services on the target system. These techniques consist in manipulating outgoing traffic so that it resembles traffic generated by a completely different system. Experimental results show that our approach can efficiently and effectively deceive an attacker.