A contract exploit allowed a hacker to mint almost 60 million PAID tokens (priced at around $160 million based on the value before the attack) on the PAID Network. The hacker then made off with about $3 million in Ethereum from their efforts. The attack caused the PAID token to crash about 88% in value over the course of a day, from around $2.86 to $0.32. The team behind the Meerkat DeFi protocol claimed they had been victims of a hack, but subsequently disappeared from the web after the equivalent of $31 million in Binance Coin (BNB) and BUSD was pulled from the project. Two days later, a developer for the project wrote that the project had been a "test [of] user greed and subjectivity", and aimed to "[help] users realize the potential danger in smart contracts [and] the subjectivity in the audit processes of audit companies." The developer wrote that all victims would be refunded. Some believed that the bizarre "experiment" explanation was to cover that Binance had stepped in to address the scam. A hacker was able to code a smart contract that tricked C.R.E.A.M. into believing it was from a trusted source. They were then able to make off with $37.5 million worth of Ethereum and stablecoins in what was only the first of several major exploits of the platform in 2021.
An exploit in Yearn.Finance's yDAI vault resulted in an $11 million loss to the platform, though "only" $2.8 million of this went to the hacker.
The stablecoin Tether swears up and down that it's fully backed by actual currency, but the New York Attorney General doesn't agree. Tether paid $18.5 million in penalties, was banned from trading in New York, and agreed to submit transparency reports for two years in exchange for ending the long-running legal dispute.