The Glassworm campaign returned with dozens of malicious packages in VS Code and Visual Studio extension marketplaces that exfiltrate tokens, credentials and source code. Security teams are urged to block unapproved extensions, run supply‑chain scans and monitor CI/CD and repository tokens for anomalous use.

Security teams are observing a resurgence of the Glassworm campaign, which is delivering malicious packages disguised as legitimate developer tools and utilities in Visual Studio and VS Code extension marketplaces. The malicious extensions are designed to harvest developer tokens, API keys, version‑control credentials and source code, creating a stealthy lateral attack path into build systems, CI/CD pipelines and internal repositories. With access to tokens and credentials, attackers can modify build artifacts, insert malicious dependencies, or exfiltrate intellectual property and sensitive configuration. The campaign represents a targeted supply‑chain threat that exploits developer trust in extension marketplaces and the elevated privileges that developer tooling commands often hold. Recommended defenses include enforcing policy allowlists for extensions, integrating supply‑chain scanning into CI workflows, rotating tokens and secrets stored on developer machines, and monitoring token usage and repository activity for anomalies. Incident responders also advise immediate revocation of compromised tokens, forensic analysis of build logs, and coordinated disclosure where third‑party codebases or customers may be affected.