SoK: A Review of Cross-Chain Bridge Hacks in 2023

Abstract: Blockchain technology has revolutionized industries by enabling secure and decentralized transactions. However, the isolated nature of blockchain ecosystems hinders the seamless transfer of digital assets across different chains. Cross-chain bridges have emerged as vital web3 infrastructure to address this challenge by facilitating interoperability between distinct blockchains. Cross-chain bridges remain vulnerable to various attacks despite sophisticated designs and security measures. The industry has experienced a surge in bridge attacks, resulting in significant financial losses. The largest hack impacted Axie Infinity Ronin Bridge, with a loss of almost \$600 million USD. This paper analyzes recent cross-chain bridge hacks in 2022 and 2023 and examines the exploited vulnerabilities. By understanding the attack nature and underlying weaknesses, the paper aims to enhance bridge security and propose potential countermeasures. The findings contribute to developing industry-wide standards for bridge security and operational resilience. Addressing the vulnerabilities and weaknesses exploited in recent cross-chain bridge hacks fosters trust and confidence in cross-chain interoperability.