Researchers say developers using Visual Studio Code (VS Code) with Claude AI may have been exposed to a serious security threat after discovering a hidden backdoor.
According to a report released by cybersecurity researchers OpenSourceMalware on October 30, version 2.1.313 of the Claude Code extension contains a hidden backdoor that could allow attackers to remotely access infected computers.
This malicious version was discovered in the Open VSX extension registry, from which developers download tools for their coding environments.
Backdoors hidden in trusted AI tools
The compromised extension allegedly appears and functions identically to the legitimate Claude Code tool, making the threat particularly difficult to detect. However, researchers discovered additional malicious code that automatically runs when the extension is loaded.
Once activated, the backdoor attempts to establish a remote connection with a server controlled by the attacker, potentially granting hackers access to the victim's computer.
More concerning, this malware is designed to remain active even after the computer restarts.
This means that simply closing VS Code or stopping the use of Claude does not eliminate the threat.
Why cryptocurrency developers need to pay attention
Although this attack was not specifically targeted at cryptocurrency users, those involved in blockchain project development may face significant risks.
Their computers may contain sensitive information, including private keys, wallet credentials, exchange API keys, and access to cryptographic infrastructure.
If an attacker successfully gains remote access, they could obtain this information and use it to compromise wallets or projects.
Has Anthropic's official extension been compromised?
Researchers confirmed that malicious code was found in the analyzed version of Open VSX, but were unable to determine how the code was inserted.
Importantly, these findings do not prove that Anthropic’s official VS Code Marketplace release or its broader distribution system was compromised.
Developers who installed version 2.1.313 via Open VSX should consider their systems potentially compromised and initiate an investigation immediately.
Simply removing the extension may not be enough, as this backdoor is designed to persist independently.