Davi Alves

By Davi Alves

Bandwidth depletion Denial-of-Service (DoS) attack can impact the propagation of a mined block in the Bitcoin blockchain network. On Bitcoin Proof-of-Work (PoW) consensus several machines try to resolve an expensive cryptographic puzzle faster than anyone else and succeed to mine a valid block. Despite a DoS attack impedes one machine to propagate its mined block allowing it to become valid for most peers, there will be several other peers to resolve the puzzle in time, hence the blockchain will continue to grow. However, from the perspective of the owner of the attacked machine, this can be critical because it will not receive a mining reward. This chapter covers such an attack in the Lisk blockchain that utilizes the Delegated Proof of Stake (DPoS) consensus mechanism. A mitigation strategy was created based on two tools that I have created allowing a delegate account to be configured in more than one node, allowing to forge a block even when one of its nodes is under DoS attack. Also, the transaction flood DoS attack is explored, and a mitigation strategy was created for a specific sidechain in the Lisk ecosystem. The mitigation strategy identifies spam transactions and rejects them to be included on the Lisk nodes transaction pool, hence they will not be propagated into the blockchain. Towards the end, I evaluated scenarios and mitigation strategies created for each attack demonstrating solutions for several scenarios.

Part of the book: Cybersecurity Threats with New Perspectives