According to the data monitoring of Chengdu Lian’an Blockchain Security Situation Awareness Platform, there were more than 12 typical security incidents in April. Ethereum and Defi continued to experience thunderstorms and various frauds were still active. Three security incidents occurred in Defi: the imBTC pool on Uniswap was re-entered by a hacker, with a loss of more than 300,000 US dollars; Lendf.me was re-entered into a similar re-entry attack in the Uniswap incident; the Hegic code error caused the user funds of 28,000 US dollars to be permanently inaccessible. One security incident occurred on the exchange: Binance Exchange was attacked and caused a wide range of contract pages to freeze. Three security incidents occurred on the dark web: Email.it was hacked and caused 600,000 user data leaks; 267 million Facebook account information was sold on the dark web for $ 600; the hacker linked Huiying Medical ’s new crown detection data to the dark web transaction. There are 4 cases of fraud and crypto scams: the “EOS Ecology” fund project involved a total amount of 360 million yuan; Telegram ’s “brick arbitrage” scam caused 900Eth losses for users; users suffered frauds by false imtoken personnel; EOS mainnet criminals deceive users Recharge. Other security incidents: PegNet was “51% attacked” this week. In general, the number of security incidents in April has decreased compared with March, but the situation in Ethereum and Defi is still grim. We recommend that when the Defi project encounters risks, it should conduct self-examination in a timely manner to find out the potential With regard to security vulnerabilities and security risks, if necessary, with the help of third-party security companies, users should avoid coveting small profits in order to prevent fraud.