ICS Protocol Fuzzing: Coverage Guided Packet Crack and Generation

Industrial Control System (ICS) protocols play an essential role in building communications among system components. Recently, many severe vulnerabilities, such as Stuxnet and DragonFly, exposed in ICS protocols have affected a wide distribution of devices. Therefore, it is of vital importance to ensure their correctness. However, the vulnerability detection efficiency of traditional techniques such as fuzzing is challenged by the complexity and diversity of the protocols.

In this paper, we propose to equip the traditional protocol fuzzing with coverage-guided packet crack and generation. We collect the coverage information during the testing procedure, save those valuable packets that trigger new path coverage and crack them into pieces, based on which, we can construct higher-quality new packets for further testing. For evaluation, we build Peach * on top of Peach, which is one of the most widely used protocol fuzzers, and conduct experiments on several ICS protocols such as Modbus and DNP3. Results show that, compared with the original Peach, Peach * achieves the same code coverage and bug detection numbers at the speed of 1.2X-25X. It also gains final increase with 8.35%-36.84% more paths within 24 hours and has exposed 9 previously unknown vulnerabilities.