BounceBit Shuts Down Blockchain After 286.5 Million Tokens Stolen

BounceBit will permanently shut down its Layer 1 blockchain following the theft of 286.5 million BB tokens from nine mainnet accounts. The project will reissue the token as a BEP-20 asset on BNB Chain. The attacker exploited a protocol-level authorization vulnerability without compromising private keys or wallets. The BounceBit Chain, built on the Evmos stack, allowed unauthorized transfers due to a bypass in the smart contract's authorization process. The attacker executed 14 transactions over 4 hours and 52 minutes on August 19 and 20, using two accounts and 15 single-use contracts. Block production ceased at height 20,702,857, approximately 42 minutes after the last transfer. Evmos has also been discontinued, and BounceBit stated that moving to a new codebase would require a complete rebuild and re-audit. The incident follows a recent security issue at MANTRA, which froze its network due to a vulnerability. For BB holders, balances will be set from block 20,697,260, and any BB tokens moved during the incident will not exist on the reissued token. Transfers made during the 5-hour-34-minute window will be reversed. BounceBit plans to credit reissued altcoins automatically to corresponding BNB Chain addresses without a claim site. BB traded near 0.0111 on Saturday, up 16% over 24 hours, but hit a record low of 0.0079 on August 20, about 31% below its pre-attack level. The stolen tokens represent approximately 13.6% of the 2.1 billion maximum supply, valued at nearly 3200000 dollars.