On Reconnaissance with IPv6: A Pattern-Based Scanning Approach

Today's capability of fast Internet-wide scanning allows insights into the Internet ecosystem, but the on-going transition to the new Internet Protocol version 6 (IPv6) makes the approach of probing all possible addresses infeasible, even at current speeds of more than a million probes per second. As a consequence, the exploitation of frequent patterns has been proposed to reduce the search space. Current patterns are manually crafted and based on educated guesses of administrators. At the time of writing, their adequacy has not yet been evaluated. In this paper, we assess the idea of pattern-based scanning for the first time, and use an experimental set-up in combination with three real-world data sets. In addition, we developed a pattern-based algorithm that automatically discovers patterns in a sample and generates addresses for scanning based on its findings. Our experimental results confirm that pattern-based scanning is a promising approach for IPv6 reconnaissance, but also that currently known patterns are of limited benefit and are outperformed by our new algorithm. Our algorithm not only discovers more addresses, but also finds implicit patterns. Furthermore, it is more adaptable to future changes in IPv6 addressing and harder to mitigate than approaches with manually crafted patterns.