Legacy MakerDAO keeper exploited for $500K in Black Thursday leftover

An old MakerDAO auction-keeper contract was targeted in an exploit totaling more than $500,000. The incident traces back to the Black Thursday event in March 2020.

CertiK's investigation details that the attacker managed to extract 200 ETH from a contract labelled a "legacy auction-keeper."

During the liquidation crisis on Black Thursday, that auction-keeper was among the first to secure ETH from MakerDAO via "zero bids". Four lots of 50 ETH each were never settled, and the hacker exploited that gap.

According to CertiK’s analysis “the root cause was a missing access control on function 0x8804d1de in keeper implementation 0x68399ed8aa33C5b43F863EE6782de492006A5546.”

Exploiting this, the attacker accessed the four outstanding lots of 50 ETH from the original Black Thursday crisis.

The funds were subsequently transferred in increments of 10 ETH via Tornado Cash.

The contract was not integral to the current Sky ecosystem, but it highlights the enduring nature of cryptocurrency risks. Even non-central contracts from years ago can remain attractive to attackers if they hold genuine value.