Hackers steal $23.7 million in crypto from Ostium in off-chain attack

Ostium, a decentralized trading platform on Arbitrum, suffered an off-chain price-feed manipulation that allowed an attacker to steal $23.75M from its liquidity provider vault by submitting fraudulent price reports and rapidly opening/closing large positions; trader collateral and existing positions were not stolen but trading was paused and positions frozen while the company investigates and tracks funds (the attacker swapped stolen USDC for ETH and deposited a large portion into TornadoCash).