Web3 Security Incident Analysis: A Certain Platform's Cold Wallet Suffered a Major Attack

On February 21, 2025, the Cold Wallet of a well-known trading platform for Ethereum was attacked, resulting in approximately 401,346 ETH, 15,000 cmETH, 8,000 mETH, 90,375 stETH, and 90 USDT being transferred to an unknown address, with a total value of around $1.46 billion.

The attacker uses phishing tactics to lure the signers of the platform's multi-signature Wallet into signing malicious transactions. The attack steps are as follows:

1. The attacker deploys a malicious contract with a backdoor for fund transfers in advance.
2. Tamper with the security management interface, causing the information about the transaction that the signer sees to be inconsistent with the data actually sent to the Cold Wallet.
3. Obtain three valid signatures through a forged interface, replace the multi-signature Wallet implementation contract with a malicious version, thereby controlling the Cold Wallet and transferring funds.

The security company entrusted with conducting the forensic investigation has currently discovered:

• Malicious JavaScript code has been injected into the cloud storage of the security management platform.
• Code analysis shows that its main purpose is to manipulate transaction content during the signing process.
• Malicious code is set with activation conditions and only triggers at specific contract addresses.
• After the malicious transaction was executed, an updated version of the JavaScript resource was uploaded, removing the malicious code.
• Preliminary assessment indicates that the attack originated from the cloud infrastructure of the security management platform.
• No signs have currently been found that the infrastructure of the platform itself has been compromised.

From the existing information, the front end is not the main issue; the key problem lies in the cloud storage service being compromised, leading to the tampering of JavaScript. However, if the security management platform's front end had implemented basic integrity verification, even if the JavaScript was altered, it would not have resulted in such severe consequences. Of course, the trading platform also cannot escape responsibility, as they confirmed transactions without specific transaction information displayed on the hardware wallet, which itself poses a risk to the trust in the security management platform's front end.

Hardware wallets have limitations when handling complex transactions, as they cannot fully parse and display the detailed transaction data of multi-signature wallets, leading signers to perform "blind signing" without fully verifying the transaction content.

Hackers are skilled at exploiting design flaws in interaction processes to deceive users and steal assets, such as UI hijacking, deceptive signatures, using blind signatures, abusing Permit signatures, TransferFrom zero transfer phishing, tail number matching airdrop scams, NFT phishing, and more.

With the development of Web3 technology, the boundaries between front-end security and blockchain security are becoming increasingly blurred. Traditional front-end vulnerabilities are given new attack dimensions in the Web3 context, while issues such as smart contract vulnerabilities and private key management flaws further amplify the risks.

Transaction Parameter Tampering: Interface Displays Transfer, Actual Execution Authorizes

The user sees a wallet pop-up displaying "Transfer 1 ETH to 0xUser...", but the actual on-chain execution is "approve(attacker, unlimited)", allowing the assets to be transferred at any time.

Solution: EIP-712 Structured Signature Verification

1. Front-end generated verifiable data
2. Smart Contract Verification Signature

In this way, any tampering with front-end parameters will result in a signature mismatch, and the transaction will automatically roll back.

Blind Signing Hijacking: Reasons for Hardware Wallet Breaches

An attacker may hijack the front-end code and send forged calldata to the hardware Wallet. The hardware Wallet screen displays normal transaction information, but what is actually executed is "approve(attacker, unlimited)."

Solution: Hardware Wallet Semantic Analysis + On-chain Secondary Verification

1. Upgrade hardware wallet firmware to support EIP-712
2. On-chain mandatory semantic matching

Conclusion

The integration of front-end security and Web3 security is both a challenge and an opportunity. This incident exposed deep-seated issues in security management and technical architecture within the cryptocurrency industry. The industry needs to comprehensively enhance its protective capabilities from various aspects such as device security, transaction verification, and risk control mechanisms to cope with increasingly complex threats. Front-end development should repeatedly verify access to DApps, wallet connections, message signing, transaction signing, and post-transaction processing to achieve a transition from "passive patching" to "active immunity." Only in this way can we safeguard the value and trust of every transaction in the open world of Web3.

Of course, the security audit of on-chain contracts is indispensable for every Dapp. AI-assisted security scanning tools can ensure code correctness through formal verification and AI-assisted security specifications, provide code similarity and intellectual property risk analysis for a large number of deployed contracts, monitor around the clock, and promptly notify of zero-day vulnerabilities and security incidents that may affect the project. Some tools also have AI models optimized based on large-scale vulnerability databases for detecting various real vulnerabilities in smart contracts.