Cross-Chain Bridge Long: The attacker stole 46.79 WETH, with no user funds lost

The managed cross-chain bridge Long released a post-mortem report on the WETH hacking incident on September 14. On that day at 07:07 UTC, the bridge paid 46.7928 WETH (approximately $118,000) to the attacker's address from the Robinhood Chain treasury. There were no user fund losses, and the treasury has been fully replenished from platform revenue. The bridge has been rebuilt, reinforced, and continues to operate. During the recovery period, some orders were delayed by several hours.

The bridge's keeper read the burn events on Arc via RPC to release assets. At that time, the official mainnet endpoint was not online, relying on public RPC. After the backup endpoint was overloaded, the main endpoint provided the keeper with forged withdrawal event logs within a short window, which did not exist on Arc. The keeper's protection at that time was against replay and double spending, and did not question the data source, thus releasing the WETH. Meanwhile, three other forged withdrawals were completely reverted on-chain. The forged events entered through the RPC channel, and the contract, keys, and treasury were not breached.