Overview

In April 2025, the total loss of Web3 security incidents was about 26.4 million US dollars. Among them, according to the SlowMist Blockchain Hacked Archive (https://hacked.slowmist.io), there were 18 hacking incidents, resulting in a loss of about 21.11 million US dollars, and 17.89 million US dollars were frozen or returned. The causes of the incidents involved contract loopholes, social engineering, internal evil and private key leakage. In addition, according to the Web3 anti-fraud platform Scam Sniffer, there were 7,565 victims of phishing incidents this month, with a loss of 5.29 million US dollars.

(https://dune.com/scam-sniffer/april-2025-scam-sniffer-scam-report)

Major security incidents

KiloEx

On April 15, 2025, the decentralized perpetual contract trading platform KiloEx was attacked, causing a loss of approximately $8.44 million. After the incident, SlowMist immediately intervened in the analysis and issued a security alert. Fortunately, with the active response of the project party and the collaboration of SlowMist and other parties, it took 3.5 days to successfully recover all the stolen assets and the incident was successfully resolved.

According to KiloEx's analysis report, the attack originated from a flaw in the contract's permission verification mechanism. The TrustedForwarder contract inherited OpenZeppelin's MinimalForwarderUpgradeable contract, in which the execute method was not overridden in TrustedForwarder and was a method that could be accessed without permission. The attacker exploited this vulnerability and directly called the original execute method of OpenZeppelin's MinimalForwarderUpgradeable. The request content of the execute method was to call the delegateExecutePositions function. In the delegateExecutePositions method, only msg.sender == trustedForwarder was verified, and it was not verified whether the real initiator was the keeper. As a result, the attacker bypassed the permission verification. In a transaction, the attacker first opened a position at an extremely low price, and then closed the position at a higher price, thereby completing the attack.

https://x.com/SlowMist_Team/status/1911991384254402737

Loopscale

On April 26, 2025, Loopscale, a modular DeFi lending market built on Solana, was attacked, resulting in the theft of approximately 5.7 million USDC and 1,200 SOL, accounting for approximately 12% of the platform's total funds. The root cause of the attack has been confirmed to be an isolated issue with Loopscale's RateX-based collateral pricing mechanism. On April 29, according to Loopscale's official Twitter account, after successful negotiations, all 5,726,725 USDC and 1,211 SOL stolen on April 26 have been returned, and user deposits have not been lost.

(https://x.com/LoopscaleLabs/status/1917212052029931624)

ZKsync

According to the incident analysis report released by ZKsync (https://zksync.mirror.xyz/W5vPDZqEqf2NuwQ5x7SyFnIxqqpE1szAFD69iaaBFnI), on April 13, a compromised administrator account minted the remaining unclaimed tokens in the ZK token Merkle distribution contract for the ZKsync airdrop on June 17, 2024. The attacker successfully controlled 111,881,122 ZK tokens (with a market value of approximately $5 million at the time). This incident was limited to three specific ZK token Merkle distribution contracts in the June 2024 ZK airdrop, and the problem was caused by the compromise of their administrator keys. On April 23, after the ZKsync Security Committee proposed a "safe harbor" agreement, the attacker returned all funds and the incident was resolved.

(https://x.com/TheZKNation/status/1915110305790660939)

R0AR

On April 16, 2025, R0AR was attacked and lost about $780,000. According to the analysis of the SlowMist security team, the root cause of the attack was the existence of a backdoor in the contract. During the deployment process, the R0ARStaking contract tampered with the balance (user.amount) of the specified address by directly modifying the storage slot. Subsequently, the attacker used the emergency withdrawal function to withdraw all the funds in the contract. Dustin, the founder and CEO of R0AR, explained the incident in an AMA. He explained in detail that the developer involved implanted malicious code in the staking contract, which enabled the emergency withdrawal operation to be performed, resulting in the liquidity pool being emptied and about 490 ETH worth of tokens being stolen. According to the analysis of MistTrack, an on-chain anti-money laundering and tracking tool, the stolen funds have been transferred to Tornado.

(https://x.com/SlowMist_Team/status/1912417097269014825)

图像Feature analysis and security recommendations

This month, the stolen funds from three hacking incidents were fully recovered. It can be seen that after an unfortunate security incident, on-chain tracking and negotiation are still one of the most critical response measures. If effective on-chain communication can be carried out in a short period of time, losses can often be recovered more efficiently. Previously, we released SlowMist: On-chain message for first aid guide for theft (https://mp.weixin.qq.com/s?__biz=MzU4ODQ3NTM2OA==&mid=2247498284&idx=1&sn=a63d4d68faa737e77951094fb085fd8b&scene=21&token=539586412&lang=zh_CN#wechat_redirect) and SlowMist: On-chain message for first aid guide for theft - BTC Article (https://mp.weixin.qq.com/s?__biz=MzU4ODQ3NTM2OA==&mid=2247501897&idx=1&sn=2cb16f9234e1483af0c175f7caac2ff6&scene=21&token=539586412&lang=zh_CN#wechat_redirect), interested readers can click to view.

On the other hand, with the rapid development of large models, various new AI tools are constantly emerging. The current representative MCP (Model Context Protocol) standard implementation tools are gradually becoming a key bridge between large language models (LLM) and external tools and data sources. However, the rapid popularization of MCP has also brought new security challenges. This month, the SlowMist Security Team released a series of MCP security special articles, suggesting that relevant project teams refer to them for self-inspection and risk reinforcement, and make defense preparations in advance.

The widespread use of AI in blockchain has also triggered new potential risks. In 2024, SlowMist disclosed the first real case of asset theft due to AI poisoning in history, indicating that using AI to attack is no longer just talk. In the future, similar forms of attack may continue to evolve. In addition, in the dark forest of blockchain, in addition to the ability to prevent AI from doing evil, it is also necessary to have the ability to verify whether it is AI doing evil. This is not only an extension of external attack defense, but also related to the identification and control of internal behavior and potential risk sources.

Finally, the events included in this article are the main security events of this month. More blockchain security events can be viewed in the SlowMist Blockchain Hacked Archive (https://hacked.slowmist.io/).