According to CoinMeta, and as monitored by SlowMist, the Balancer V1 fund pool was attacked, resulting in a loss of approximately $234,000. The attackers exploited a precision issue with joinswappoolamountout of bpool, pushing the reserves of WBTC to extremely low levels. They then minted a large quantity of BPT for about 1聪 of WBTC, and subsequently withdrew assets such as DPI, USDC, WETH, and WBTC in proportion.