Leveraging Bitcoin Testnet for Bidirectional Botnet Command and Control Systems
This addresses a cybersecurity threat for botnet operators by making C&C systems more resilient, though it is incremental as it builds on prior Bitcoin-based methods.
The paper tackles the problem of botnet Command and Control (C&C) systems being vulnerable to disruption by proposing a method using Bitcoin Testnet to create a cost-free, bidirectional, and encrypted C&C channel, with results indicating it enables a robust and hard-to-disrupt system at virtually no cost.
Over the past twenty years, the number of devices connected to the Internet grew exponentially. Botnets benefited from this rise to increase their size and the magnitude of their attacks. However, they still have a weak point in their Command & Control (C&C) system, which is often based on centralized services or require a complex infrastructure to keep operating without being taken down by authorities. The recent spread of blockchain technologies may give botnets a powerful tool to make them very hard to disrupt. Recent research showed how it is possible to embed C&C messages in Bitcoin transactions, making them nearly impossible to block. Nevertheless, transactions have a cost and allow very limited amounts of data to be transmitted. Because of that, only messages from the botmaster to the bots are sent via Bitcoin, while bots are assumed to communicate through external channels. Furthermore, for the same reason, Bitcoin-based messages are sent in clear. In this paper we show how, using Bitcoin Testnet, it is possible to overcome these limitations and implement a cost-free, bidirectional, and encrypted C&C channel between the botmaster and the bots. We propose a communication protocol and analyze its viability in real life. Our results show that this approach would enable a botmaster to build a robust and hard-to-disrupt C&C system at virtually no cost, thus representing a realistic threat for which countermeasures should be devised.