Ronin Network lost 173,600 ETH and 25.5 million USDC, about $624 million, after attackers used compromised validator access to forge withdrawals from the Ronin Bridge. The exploit depended on Ronin's five of nine validator approval model: four Sky Mavis validators were compromised, and an old Axie DAO whitelist still allowed the attackers to obtain the fifth signature. The stolen funds were moved across multiple addresses and chains to complicate tracing, and Ronin later raised its transaction approval threshold to eight of nine validators.