New Pectra Vulnerability Exposes Ethereum Wallets to Offchain Signature Attacks

Ethereum's recent network upgrade, Pectra, has inadvertently introduced a significant vulnerability that allows hackers to drain user wallets using only offchain signatures. This flaw, stemming from the new transaction type introduced in the upgrade, poses a serious risk to users who may unknowingly authorize malicious actions.

Key Takeaways

Pectra upgrade went live on May 7, 2025, introducing a new transaction type that can be exploited.
Attackers can drain funds from externally owned accounts (EOAs) using only an offchain signed message.
The vulnerability is linked to Ethereum Improvement Proposal (EIP) 7702, which allows delegation of wallet control.
Users are urged to be cautious and validate any messages they sign to avoid exploitation.

Understanding the Pectra Upgrade

The Pectra upgrade was designed to enhance Ethereum's scalability and smart account functionality. However, it has also opened a new attack vector that could be exploited by malicious actors. The core of this vulnerability lies in EIP-7702, which introduces a new transaction type (0x04) that enables users to delegate control of their wallets simply by signing a message.

This means that if an attacker gains access to a user's offchain signature—potentially through phishing schemes—they can overwrite the wallet's code with a proxy that redirects calls to their malicious contract. As a result, the attacker can transfer funds from the user's account without requiring any direct onchain transaction approval from the user.

The Mechanics of the Attack

Offchain Signature Exploitation: Attackers can exploit the new transaction type to drain funds from EOAs without needing an onchain transaction.
Phishing Risks: Common phishing tactics, such as fake DApps or misleading emails, can be used to trick users into signing malicious messages.
Wallet Vulnerability: Wallets that do not properly analyze Ethereum's transaction types, especially type 0x04, are particularly at risk.
Hardware Wallets at Risk: Even hardware wallets, traditionally considered secure, are now vulnerable if they sign malicious messages.

User Precautions

To mitigate the risks associated with the Pectra vulnerability, users should take the following precautions:

Validate Signatures: Always ensure that you understand the messages you are signing. If a message includes your account nonce, it may directly affect your account.
Be Wary of New Formats: New delegation signature formats introduced by EIP-7702 may not be compatible with existing standards, making them harder to detect.
Use Multisignature Wallets: These wallets require multiple signers, providing an additional layer of security against unauthorized transactions.
Stay Informed: Keep up to date with developments in Ethereum and be aware of potential vulnerabilities that may arise from upgrades.

Conclusion

The Pectra upgrade has brought significant advancements to Ethereum but also introduced a critical vulnerability that users must navigate carefully. As the crypto landscape evolves, it is essential for users to remain vigilant and informed about the security of their wallets. By understanding the risks and taking proactive measures, users can better protect their assets in this rapidly changing environment.

Sources

Here’s what happened in crypto today — TradingView News, tradingview.com.
Pectra lets hackers drain wallets with just an offchain signature, Cointelegraph.

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