Eclipse Attacks on Monero's Peer-to-Peer Network

—Eclipse attack is a major threat to the blockchain network layer, wherein an attacker isolates a target node by monopolizing all its connections, cutting it off from the rest of the network. Despite the attack’s demonstrated effectiveness in Bitcoin (Usenix’15, SP’20, Usenix’21, CCS’21, SP’23) and partially in Ethereum (NDSS’23, SP’23), its applicability to a wider range of blockchain systems remains uncertain. In this paper, we investigate eclipse attacks against Monero, a blockchain system known for its strong anonymity and pioneering the use of Dandelion++ (the state-of-the-art blockchain network layer protocol for transaction privacy protection). Our analysis of Monero’s connection management mechanism reveals that existing eclipse attacks are surprisingly ineffective against Monero. We accordingly introduce the first practical eclipse attack against Monero by proposing a connection reset approach, which forces the target node to drop all benign connections and reconnect with malicious nodes. Specifically, we outline two methods for executing such an attack. The first one exploits the private transaction mechanisms, while the second method leverages the differences in propagation between stem transactions and fluff transactions under Dandelion++. Our attack is not only applicable to Monero but to all blockchain systems utilizing Dandelion++ and similar connection management strategies. We conduct experiments on the Monero mainnet. Evaluation results confirm the feasibility of our attack. Unlike existing eclipse attacks, our connection reset-based approach does not require restarting the target node, significantly accelerating the attack process and making it more controllable. We also provide countermeasures to mitigate the proposed eclipse attack while minimizing the impact on Monero. In addition, we have ethically reported our investigation to Monero official team