Symbiosis Bitcoin Bridge Exploit Results in $336,000 Loss
An exploit of Symbiosis's Bitcoin Bridge led to a significant loss of funds. The attacker minted unbacked syBTC and sold WBTC on Ethereum.
An attacker exploited Symbiosis’s Bitcoin Bridge (BridgeV2), resulting in the minting of approximately 2622^{62}2^{62} raw unbacked syBTC on BNB Chain. This action allowed the attacker to sell around 4.39 WBTC on Ethereum's Uniswap V4 for a total of about $336,000. In response, the Symbiosis team paused native BTC routes to mitigate further losses.
The team reported recovering approximately 15 BTC into a team multisig wallet following the incident. Additionally, they announced a 20% bounty for white-hat hackers who could assist in the recovery of funds. The incident highlights vulnerabilities within the bridge mechanism, which allowed for the minting of unbacked tokens.