Decentralized finance (DeFi) hacks remain a major threat to the industry, despite a decline in stolen amounts in 2023, according to a report from blockchain security firm Halborn. The report summarizes the 100 largest DeFi hacks between 2016 and 2023, totaling $7.4 billion, with most attacks occurring on Ethereum, Binance Smart Chain, and Polygon. The report added that only 21% of hacked protocols used multi-signature wallets, a security method that requires multiple people to approve transactions at the same time. Halborn also warned that most on-chain attacks occurred on unaudited protocols, and that the lack of incorrect input validation or confirmation in protocols was the main cause of losses in smart contract exploits. Cross-chain bridges remain the main attack vector for malicious actors, and protocols should "carefully review their code" before using cross-chain bridges. (CoinDesk)