GitHub has confirmed a major security breach involving around 3,800 internal code repositories after hackers compromised an employee’s device using a malicious Visual Studio (VS) Code extension. The company says the incident was detected on 19 May and is currently under investigation.
The attack has been linked to cybercrime group TeamPCP, which later claimed responsibility on dark web forums. According to the group, the stolen data includes GitHub source code and internal projects, which it is allegedly attempting to sell for at least US$50,000 (~RM198,000). TeamPCP also claimed that the data would either be sold to a buyer or leaked publicly if no deal is reached.
What Happened?
GitHub says the attackers gained access after an employee installed a poisoned VS Code extension. Once the device was compromised, the hackers were able to steal credentials and access thousands of GitHub’s own internal repositories. The company noted that TeamPCP’s claim of around 3,800 repositories being affected is “directionally consistent” with its current findings.
Importantly, GitHub stressed that the breach only involved its internal repositories and did not affect customer projects or public repositories hosted on the platform. The stolen data reportedly includes parts of GitHub’s internal infrastructure, such as code related to GitHub Actions, Copilot projects, agentic workflow systems, and Rails controllers used for pull request management.
Allegedly Linked To Backdoored VS Code Extension
While GitHub has not publicly identified the malicious extension involved, security researchers believe the breach is connected to a recent supply chain attack targeting the popular Nx Console extension for VS Code. The extension, which reportedly has more than 2.2 million installs, was briefly compromised after attackers gained access to a developer token.
That malicious update allegedly harvested sensitive credentials from developers, including GitHub access tokens, SSH keys, cloud credentials and API keys linked to services such as AWS and Claude Code. Those credentials were then reportedly used to compromise additional developer tools and services, allowing the attack to spread further.
Researchers have also linked TeamPCP to a self-propagating malware strain known as “Mini Shai-Hulud.” The worm is designed to automate parts of the attack chain by creating new GitHub repositories to store stolen credentials, while also spreading compromised updates to other software packages and tools.
Actions Taken
Following the discovery of the breach, GitHub says it immediately isolated the compromised employee device, removed the malicious extension from the VS Code Marketplace, and rotated critical secrets and credentials overnight to prevent further abuse. The company also says it has reviewed logs, monitored for additional suspicious activity, and launched a broader incident response investigation. GitHub plans to publish a more detailed report once the investigation is completed.
(Source: WIRED)
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