Euler suffered a $200 million Hacker attack, affecting multiple DeFi projects.

Euler Finance, as one of the few innovative DeFi projects after DeFi Summer, categorizes its assets into different tiers based on their risk levels, with each tier having different borrowing permissions. However, on March 13, the project was attacked by a Hacker, resulting in a loss of approximately $200 million.

As a foundational lending protocol, the security of Euler is particularly important. Due to the composability of Decentralized Finance, this attack also affected several other DeFi projects, resulting in losses of tens of millions of dollars.

Angle Protocol is a decentralized non-USD stablecoin project that primarily provides the euro stablecoin agEUR. Users can mint agEUR in two ways: first, by exchanging stablecoins like USDC 1:1 through the core module, with price volatility risk borne by the hedge agents of leveraged trading rates; second, by minting through the lending module with over-collateralization using assets like WETH. To increase project surplus and incentivize token holders, Angle developed a yield strategy referencing Yearn, using the collateral for minting agEUR in the core module to generate returns. In this attack, Angle estimated a loss of $17.61 million; although there is a surplus of $5.58 million, it is still insufficient for full compensation, and compensation will be made proportionally to agEUR holders, liquidity providers, and the funds for hedge tokens.

A certain DEX suffered a loss of $11.9 million due to bbeUSD (Euler Boosted USD) in this attack. This DEX launched the Boosted Pools innovation in December 2021, aiming to improve LP yield and facilitate users' entry or exit from lending protocols. Part of the funds in Boosted Pools is deposited into lending protocols, while the remaining portion is available for user trading. In the DEX's Boosted Euler USD pool, users can deposit three stablecoins: USDT, USDC, and DAI. These funds are then deposited into Euler, and users receive LP tokens bbeUSD. bbeUSD can be paired with other tokens to earn liquidity mining rewards. This move not only promotes the use of bbeUSD but also increases the amount of loss incurred in this incident.

Idle Finance, as a yield aggregator, offers three yield strategies: Best Yield, Senior Tranches, and Junior Tranches. Junior Tranches have higher risk and yield, and may need to bear losses before Senior Tranches in the event of a security incident. Idle Finance deposits funds such as DAI, USDT, and ETH into multiple projects to automatically generate yields and reinvest. Due to a tendency to choose high-yield strategies, Euler Finance has become an important partner. In this attack, Idle Finance's Best Yield Vault and Yield Tranches had risk exposures to Euler Finance of $5.3271 million and $5.6628 million, respectively, totaling approximately $10.99 million.

Yield Protocol is a fixed-rate lending protocol that operates similarly to zero-coupon bonds. Depositors receive fyTokens, which can be redeemed for the underlying asset at a 1:1 ratio after the maturity date and can be traded at a discount before maturity. A portion of the liquidity pool's funds is deposited in Euler, while some hold fyTokens. It is expected that the funds deposited in Euler before the attack were less than $1.5 million, while the collateral of borrowers remains unaffected as it is held in Yield Protocol.

A certain yield aggregator stated that its yvUSDT and yvUSDC have a risk exposure of $1.38 million to Euler due to the strategies employed by Idle and Angle. The resulting bad debt will be borne by its Treasury, and all Vaults are still operating normally.

Another yield aggregation platform stated that its USDC, USDT, and WETH Vaults are affected by the use of Idle, but has not yet announced a specific handling plan, and reminds users not to interact with these Vaults for the time being.

The dollar stablecoin DOLA from Inverse Finance suffered liquidity loss on a certain DEX due to the DOLA/bbeUSD trading pair. Despite taking proactive measures to mitigate the losses, DOLA Fed still incurred a loss of $860,000.

A certain cryptocurrency asset management platform stated that its Earn strategy suffered losses in the ETH and USDT portions, including 1617.23 ETH and approximately 1.69 million USDT, accounting for 2.27% and 29.52% of the subscribed capital, respectively. The platform will bear all losses.

Opyn has built the first decentralized options protocol and developed perpetual options Opyn Squeeth along with various yield strategies. The impacted strategy is its Zen Bull strategy, which combines the Crab strategy and leveraged long positions in ETH, suitable for low-volatility markets with an upward trend in ETH prices. Since the strategy requires collateral assets to leverage buy ETH, it may lead to losses due to collateral borrowing on Euler. Opyn has not yet disclosed the specific amount of losses and its handling plan.

Sherlock, as a DeFi security provider, previously reached a $10 million collaboration with Euler to audit smart contracts and provide insurance. After Euler was attacked, Sherlock voted to pay $4.5 million to Euler and executed a compensation of $3.3 million.

Sense Finance is a fixed-rate lending protocol, where fixed-income assets such as Idle can be traded, thus being indirectly affected.