Malicious VS Code Extensions Harvest Developer Source Code

PackageGate Flaws Affect JavaScript Package Managers

Security researchers discovered two malicious VS Code extensions – ChatGPT - 中文版 and ChatGPT - ChatMoss – boasting 1.5 million combined installs, that secretly transmit developer source code to China-based servers, an operation dubbed “MaliciousCorgi”. These extensions function as advertised, lowering user suspicion while simultaneously capturing and sending sensitive data.

Why This Matters

Current software development relies heavily on third-party extensions and package managers, creating a complex supply chain. The assumption of trustworthiness in these tools is often misplaced, as demonstrated by this incident. Failing to secure this supply chain can lead to widespread intellectual property theft, potentially costing organizations millions in damages and impacting national security.

Key Insights

• 1.5 million installs: Combined total of malicious VS Code extensions before discovery.
• PackageGate: Six zero-day vulnerabilities found in JavaScript package managers (npm, pnpm, vlt, Bun) that bypass security controls.
• Base64 Encoding: Method used by the extensions to obscure and transmit stolen source code.

Working Example

# Example of Base64 encoding/decoding in Python.
import base64

# Sample source code (replace with actual code)
source_code = "print('Hello, world!')"

# Encode the source code to Base64
encoded_code = base64.b64encode(source_code.encode('utf-8'))
print(f"Encoded: {encoded_code.decode('utf-8')}")

# Decode the Base64 encoded string
decoded_code = base64.b64decode(encoded_code).decode('utf-8')
print(f"Decoded: {decoded_code}")

Practical Applications

• Continuous Monitoring: Companies like Palo Alto Networks utilize threat intelligence platforms to proactively identify and block malicious extensions.
• Pitfall: Relying solely on extension popularity as an indicator of safety can leave developers vulnerable to supply chain attacks, as demonstrated by the widespread adoption of the malicious extensions.

References:

• https://thehackernews.com/2026/01/malicious-vs-code-ai-extensions-with-15.html