Bitcoin DeFi application ALEX Lab lost more than $4.3 million in cryptocurrency in an attack early Wednesday, and it is suspected that the private key leak caused its cross-chain service to be attacked. Certik said that the attacker may have a private key that controls ALEX's XLink bridge. ALEX developers have confirmed the hack and claimed to know the identity of the attacker, offering the hacker a 10% bounty to recover 90% of the stolen funds. In addition, the ALEX team said that the hacker-related funds have been frozen by major exchanges to prevent further abuse. (CoinDesk)