Safeguarding Web3: Unraveling a Web 2.0 Vulnerability in WalletConnect's Verify API

Safeguarding Web3: Unraveling a Web 2.0 Vulnerability in WalletConnect's Verify API


The emergence of Web3 brings forth a new era of cybersecurity challenges and opportunities. Security considerations now extend across smart contracts, blockchain technology, decentralized finance (DeFi), and tokenomics. Flash loan attacks, re-entrancy vulnerabilities, price manipulation, and other threats are at the forefront of Web3 security concerns. It's crucial to recognize the interplay between Web3 innovations and traditional Web 2.0 components, as many Web3 products integrate Web 2.0 elements, opening the door to a range of attack vectors.

At Vibranium Audits, our mission is to secure the Web3 world. In this post, we explore a Web 2.0 vulnerability discovered in the API of a popular wallet communication protocol used in Web3.

Uncovering and Resolving a Cross-Site Scripting Attack

WalletConnect and the Verify API

WalletConnect, an open-source protocol connecting decentralized applications (DApps) with crypto wallets, introduced the "Verify API" to enhance security. This API alerts users when connecting to potentially suspicious domains, preventing phishing attacks. However, a vulnerability in the API was uncovered during a routine penetration test.

Vulnerability Discovery

The vulnerability came to light while testing a client's web application that utilized WalletConnect. An HTTP request caught our attention, leading to the identification of a potential XSS vulnerability in the Verify API.

Exploiting the Vulnerability

The XSS vulnerability allowed for the injection of malicious scripts. To validate the potential threat, our team crafted a demonstration payload, creating a phishing website that urged users to consent to a transaction, essentially granting token allowances without their knowledge.


Upon detecting the XSS vulnerability, our team compiled a detailed report and promptly reached out to WalletConnect. The remediation included an update to the validate_format function, adopting a whitelist approach to significantly diminish the risk of XSS exploitation.

Lessons Learned and Best Practices

This incident underscores the persistence of Web 2.0 vulnerabilities in Web3 and emphasizes the need for proactive security measures. Regular audits, penetration tests, and staying informed about the latest security developments are crucial practices for organizations to preemptively identify and address emerging threats.


In unraveling this reflected XSS vulnerability within WalletConnect's Verify API, we commend WalletConnect for their rapid response and effective remediation efforts. This incident highlights the ongoing evolution of security challenges and the imperative for constant vigilance and proactive security measures in the dynamic Web3 landscape.


Q1: What is the Verify API's role in WalletConnect?A1: The Verify API enhances security by alerting users to potentially malicious domains during connections, mitigating phishing threats.

Q2: How was the vulnerability discovered?A2: The vulnerability was uncovered during a routine penetration test on a client's web application using WalletConnect.

Q3: What actions were taken for mitigation?A3: WalletConnect swiftly addressed the issue by updating the token validation function to minimize the risk of XSS exploitation.

Q4: What best practices are recommended for Web3 security?A4: Regular audits, penetration tests, and staying informed about emerging security threats are crucial for maintaining robust Web3 security.

In the ever-evolving landscape of Web3, Vibranium Audits remains committed to uncovering vulnerabilities, collaborating for swift resolutions, and contributing to the overall security of the Web3 community.

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