Recently, as I look back on the dark days of DeFi in April, I still can’t shake off a lingering sense of unease. In just 18 days, losses to the ecosystem exceeded 600 million, and the story behind those numbers is even more alarming than the numbers themselves.

It all began with the Drift Protocol. On April 1, many people thought it was an April Fools’ joke—only to have 285 million dollars wiped out within 12 minutes. Later, it was discovered that North Korea’s Lazarus group had spent half a year infiltrating the system, using everything from social engineering and in-person handoffs to planting malware, and finally gaining management permissions to drain multiple vaults in one fell swoop. What does this show? No matter how airtight on-chain security is, if offline management processes fail, multi-signature wallets become nothing more than decorations.

Next, the Hyperbridge cross-chain bridge was attacked. The hackers exploited a vulnerability in Merkle proof verification to conjure 1 billion virtual DOT out of thin air. But this wasn’t the most serious part. On April 18, Kelp DAO’s rsETH was badly hit. By combining RPC infiltration with DDoS attacks, the attacker forged 116,500 rsETH (about 292 million dollars). These fake tokens were then deposited as collateral into Aave and Compound, allowing loans of 236 million dollars’ worth of WETH.

The real disaster lay in the domino effect. As the largest lending market, Aave saw users run leveraged loop borrowings on rsETH—depositing LRT, borrowing ETH, and then exchanging for more LRT. When market volatility hit, everything collapsed instantly. Within 48 hours, more than 6 billion dollars fled Aave, and the entire DeFi market’s TVL evaporated by 13 billion.

I noticed an interesting phenomenon: when Aave’s USDC annualized yield fell to 2.61%, below the 3.14% offered by traditional brokers, users’ motivation to bear smart contract risk disappeared. Any security concern was enough to cause leveraged funds to scatter in an instant. This reflects that the DeFi yield landscape is changing, and the risk-pricing mechanism needs to be rethought.

Interestingly, in the middle of the crisis, compromises were also visible. Arbitrum’s security council froze 30.7k ETH belonging to the attacker, and Tether, in coordination with law enforcement agencies, froze 344 million USDT. These actions earned praise, but they also raised real-world questions about the ideals of decentralization—when survival is threatened, multi-signature control is activated.

Post-disaster reconstruction is underway. Aave has raised about 243 million dollars to compensate for bad debts, and developers have begun shifting toward MPC wallets, ZK cross-chain bridges, and more defensive verification systems.

The lessons from this April crisis are clear: when chasing yield, you must account for composability risk, and security, decentralization, and availability must evolve in tandem. Otherwise, no matter how much technological innovation comes, it won’t be able to hold up.