AI pipelines fuel attacks on unverified smart contracts

Chainalysis reported that AI-driven exploit pipelines scanned decompiled bytecode and were used to exploit unverified smart contracts, resulting in at least $36.7 million stolen over the past six months.

The firm identified decompilers such as Dedaub, Heimdall and Panoramix that convert raw bytecode into readable Solidity. Large language models then analyze the decompiled output to flag issues including reentrancy bugs, missing access controls and arithmetic errors. When these tools are linked into automated pipelines, they can scan and triage thousands of unverified contracts quickly.

Chainalysis tied four contract exploits to this pattern, totaling $36.7 million. The largest incident occurred on Jan. 8, when an attacker drained $26.2 million from Truebit. The vulnerable contract had remained unverified on Ethereum since 2021 and contained an integer overflow in its bonding curve that allowed the attacker to mint tokens at minimal cost and burn them for ETH.

The same address had drained the Sparkle protocol for 5 ETH twelve days earlier. Proceeds from both exploits were laundered through Tornado Cash, Chainalysis found.

The report characterized the activity as methodical and included this passage: “What once required a skilled reverse engineer spending days on a single contract can now be partially automated across an entire blockchain’s unverified contract inventory. Attackers operating these pipelines gain a structural advantage: they can cover far more ground than the defenders monitoring for suspicious activity.”

Research from Anthropic cited in the report found AI agents can perform advanced attack steps on smart contracts, including on contracts deployed after the agents’ knowledge cutoffs. Security researchers have raised concerns that AI tools can outpace human auditors and lower the technical barrier for complex exploits.

Chainalysis reported that many major decentralized finance projects verify source code on block explorers, but some leave contracts unverified. Those unverified contracts are not readable by white-hat researchers, and several protocols excluded unverified contracts from their bug bounty programs.

Chainalysis recommended that protocols verify all deployed code, extend bug bounty coverage to include previously closed contracts, and adopt real-time on-chain monitoring to detect and respond to suspicious activity. The firm said it expects decompilation and AI tools to improve as the pool of unverified contracts grows.