Cardano wallet SecondFi is winding down after attackers exploited a flaw in its transaction signing software to steal 16.1 million ADA, worth roughly $2.4 million, from 374 wallets. The service, which replaced EMURGO’s Yoroi wallet, said it will not resume normal operations despite patching the vulnerability.and at the time securing 129 million ADA before attackers could reach the funds.