Key Takeaways:
Blockchain security firms are warning crypto protocols to reaudit legacy smart contracts as AI-powered tooling enables hackers to identify vulnerabilities faster than traditional audit cycles can address.
"An audit built for last year's attack patterns leaves a protocol exposed to this year's as bad actors are changing up," Ari Redbord, head of policy at TRM Labs, said. "Our data argues for continuous review rather than a one-time audit."
CertiK reported Monday that hackers stole $1.32 billion across 182 incidents in the first half of 2026, even as total losses fell roughly 60% from $2.37 billion a year earlier. The data points to a split between frequency and severity — more attacks landed, yet the biggest sums concentrated in a handful of high-value targets.
Contract and logic vulnerabilities accounted for 85 incidents, the most of any category, according to SlowMist's mid-year report. Supply chain attacks caused the largest losses at roughly $298 million, dominated by the Kelp DAO exploit that drained nearly $292 million. Researchers tied that attack to a subgroup of North Korea's Lazarus Group. Private key and credential compromises added about $130 million in losses, while contract flaws accounted for roughly $152 million. Ethereum was the most targeted ecosystem, with about $134 million in related losses.
AI Agents Reshape the Attack Surface
SlowMist highlighted artificial intelligence as a growing threat vector, noting that AI has lowered the barrier to social engineering and automated attacks. Attackers now use AI across the full attack chain. In one case, a Lazarus subgroup known as HexagonalRodent baited developers with fake job offers to plant backdoored code, using ChatGPT and Cursor to generate code and craft communication content.
AI agents themselves also emerged as targets. In a May 2026 incident, an attacker airdropped an NFT that unlocked high-privilege transfers, then sent the chatbot Grok a Morse code message that it decoded into a hidden transfer instruction. The linked trading agent BankrBot treated that output as trusted and moved about $175,000 on-chain. SlowMist classified this as an "AI agent trust chain" attack.
Defunct Protocols Become Fresh Targets
Hackers have begun exploiting the codebases of defunct decentralized finance protocols, draining millions in customer funds. On June 14, an attacker exploited a smart contract vulnerability to steal $2.1 million from Aztec Connect, which had been shut down since March 2023. Five days later, a smart contract on the decentralized exchange mySwap was exploited for $300,000, even after its user interface had been closed to new liquidity deposits for more than six months.
CertiK warned that these attacks were likely "aided by improved automated tooling for identifying latent vulnerabilities at scale." The firm said projects operating legacy infrastructure should treat reauditing as a recurring operational requirement rather than a one-time exercise.
In a more fortunate case, white hat hacker "0xflorent" recovered 1,003 Ether worth over $1.72 million in May from 48 investors involved in the 2016 Hong Coin initial coin offering. The ICO failed to launch after missing its funding target, and funds remained locked in a smart contract due to a bug in the auto-refund function.
Zcash Bug Found by AI Agent
Privacy-focused blockchain Zcash patched a critical vulnerability in its Orchard shielded pool after Shielded Labs security engineer Taylor Hornby discovered the bug using a custom auditing agent powered by Anthropic's Claude Opus 4.8. The vulnerability, which existed for four years, could have enabled undetectable counterfeiting inside one of the network's key privacy features.
Anthropic conducted a study in December finding that AI agents identified $4.6 million worth of exploitable vulnerabilities in smart contracts. With more than $72.3 billion in crypto locked across hundreds of DeFi protocols, according to DefiLlama, the incentive for attackers to exploit vulnerable code continues to grow.
"The window of maximum vulnerability does not close after launch," CertiK warned. Redbord added that the broader industry and regulators need to continue finding ways to mitigate malicious activity from North Korea and disrupt Chinese money laundering networks. "Protocols can lock their doors, but someone still has to go after the actor breaking in," he said.
This article is for informational purposes only and does not constitute investment advice.
