OnyxDAO Hack

On September 26th, 2024, Onyx DAO, a decentralized finance (DeFi) protocol derived from Compound Finance, was exploited due to a precision vulnerability, resulting in a loss of approximately $3.8 million, primarily in VUSD stablecoins.

The attackers took advantage of a known precision loss vulnerability in the forked Compound V2 code that Onyx DAO implemented. By deploying a malicious contract, they manipulated the market’s exchange rates within the protocol, artificially inflating the value of small deposits. This allowed them to withdraw 4.1 million VUSD along with other cryptocurrencies, such as XCN, DAI, WBTC, and USDT.

The attackers executed multiple transactions to miscalculate and inflate their token values, minting excessive amounts of VUSD, which they then converted to other cryptocurrencies. While some of the stolen funds were swapped into ETH, a significant portion remained unswapped, suggesting a strategic move to avoid detection.

Attacker’s Address: 0x085bdff2…642bff

Malicious Contract: 0x526e8e98…67336f

Vulnerable Contract Address: 0x5fdbcd61…a11750

Attack Transaction Hash: 0xf7c21600…6ef635