Symbiosis recovers 15 BTC after bridge hack, liquidity providers still await compensation

Cross‑chain protocol Symbiosis reported the recovery of roughly 15 BTC after an attacker exploited its native Bitcoin Bridge on September 11. The breach minted a massive amount of synthetic Bitcoin (syBTC) on BNB Chain, but the protocol says other routes and components—including those on EVM chains, TRON and TON—remained operational.

Bridge exploit and initial response

The attack occurred at about 04:28 UTC on September 11. Symbiosis halted Bitcoin‑related swaps on its native bridge while updates were deployed, but kept partner‑routed swaps through Chainflip and THORChain active. The recovered BTC is held in a team‑controlled multisig wallet, and final accounting is still in progress.

Details from security analysis

Security firm Blockaid identified a transaction signed by Symbiosis’s BridgeV2 that minted approximately 2^62 raw units of syBTC to a newly created wallet on BNB Chain. The same address later sold about 4.39 WBTC on Ethereum, generating roughly $336 000 in proceeds at the time of the alert. Blockaid’s figures reflect only the value it observed being converted, not the total loss or exposure of liquidity providers.

Compensation and bounty offer

Symbiosis is contacting each affected liquidity provider and developing a compensation framework, though criteria, eligibility and timing have not been disclosed. The protocol also offered a 20 % white‑hat bounty for information leading to recovery, available until September 13; after that date, the same percentage will apply to any subsequent tips.

Outstanding questions

• Confirmed loss and exposure figures for liquidity providers.
• Specific compensation criteria and payout schedule.
• Future status of the native Bitcoin Bridge.

Until Symbiosis publishes these details, the 15 BTC recovery and Blockaid’s proceeds estimate should not be considered a final loss tally.