According to CoinMeta, an older version of a bidder contract for MakerDAO was exploited, resulting in losses of over $500,000. This attack can be traced back to Black Thursday in 2020. An analysis of Certik details how the attackers removed 200 ETH from a contract known as the “old bidder” contract. This contract was one of the first to win ETH from MakerDAO with a “zero bid” during Black Thursday. Four batches of 50 ETH were never settled, and it was this that the attackers took advantage of. The root cause of this attack was a lack of access control in a function implemented by the bidder. Through this vulnerability, the attackers obtained four batches of 50 ETH, which were then transferred through Tornado Cash in batches of 10 ETH. Although this contract is not a core part of the current Sky ecosystem, it serves as a reminder that the long-tail effects of cryptocurrency risks still exist. Even contracts that have not been noticed for half a century can still be attractive targets for attackers if they contain real value.