Cybersecurity researchers have reported that a backdoor was discovered in a popular Visual Studio Code (VS Code) extension for Claude AI, raising concerns for developers, particularly those working in the cryptocurrency sector.
Backdoor found in widely used AI coding extension
A report from OpenSourceMalware on October 30 revealed that version 2.1.313 of the Claude Code extension, available through the Open VSX registry, contained malicious code. This extension is intended to provide AI-powered coding assistance via Claude, Anthropic’s advanced artificial intelligence tool.
The researchers stated that the compromised version closely resembled the authentic Claude Code extension in both appearance and basic functionality, making it difficult for users to detect any suspicious behavior. They found, however, that additional, unauthorized code was embedded within the tool, programmed to execute whenever the extension was initialized.
The malicious extension attempted to create a remote connection to a server controlled by attackers upon activation, potentially granting them unauthorized access to affected computers.
According to researchers, the malware aimed to remain functional even after a system reboot. As a result, closing VS Code or disabling the extension might not resolve the security incident. The extension persisted on systems, enabling potential ongoing exploitation.
The Open VSX registry, where the malicious version was distributed, serves as a platform for developers to download and install coding tools for VS Code and compatible editors.
Mini dictionary: Open VSX registry is an open-source extension marketplace that provides repositories for VS Code compatible tools, enabling wide ecosystem distribution and easier access for independent developers.
Risks for cryptocurrency developers
While the backdoor was not specifically crafted to target cryptocurrency industry professionals, researchers emphasized that developers building blockchain or crypto-related projects could be at heightened risk.
Workstations used for blockchain development frequently hold confidential data, such as private keys, wallet information, and exchange API credentials. Unauthorized remote access could result in the theft of these assets or compromise of sensitive project infrastructure.
Developers working with crypto projects should recognize that persistent backdoors may threaten not only project security but also personal and enterprise-level wallets where critical access is stored.
| Extension | Distribution Registry | Status |
|---|---|---|
| Claude Code v2.1.313 (malicious) | Open VSX | Backdoor detected |
| Official Claude Code | VS Code Marketplace | No compromise reported |
Researchers did not identify any confirmed cases of stolen cryptocurrency, nor did they find blockchain-specific attack features within the analyzed code. However, they recommended that developers using the affected version of the extension should assume their machines are compromised and investigate immediately.
Extension removal and developer response
The team at OpenSourceMalware found clear evidence of the malicious payload in Open VSX’s extension but could not determine exactly how it was introduced. They reported that the backdoor was designed to persist independently of the original extension, so uninstalling the tool may not fully eliminate the security threat.
Anthropic, an artificial intelligence research company and developer of Claude, has not reported any compromise to the official Claude Code distribution via the VS Code Marketplace or its other channels. The researchers also have not provided evidence that Anthropic’s own release pipeline was breached.
Security experts urge developers who installed Claude Code version 2.1.313 via Open VSX to treat their systems as potentially compromised, run full security assessments, and consider further remediation steps beyond simply uninstalling the extension.
