Threat actors are spreading malicious extensions via VS marketplaces

"Careless developers publishing Visual Studio extensions to two open marketplaces have been including access tokens and other secrets that can be exploited by threat actors, a security vendor has found. The discovery was made earlier this year by researchers at Wiz, who quietly worked with Microsoft and its VSCode Marketplace as well as those behind the OpenVSX marketplace to improve guardrails in their platforms. It released a report on its investigation this week."

"Wiz found over 550 validated secrets, distributed across more than 500 extensions from hundreds of VS extension publishers. They included AI provider secrets for platforms such as OpenAI, Gemini, Anthropic, xAI, DeepSeek, HuggingFace, and Perplexity; high risk profession platform secrets for AWS, Github, Stripe, Auth0, and Google Cloud Platform; and database secrets for MongoDB, Postgres, and Supabase. Over 100 valid leaked Azure DevOps Personal Access Tokens were identified within VSCode Marketplace extensions. Together, they represented an install base of over 85,000 extension installs."

"Over thirty leaked OVSX access tokens were identified, within either VSCode Marketplace or OVSX extensions. Together they represented over 100,000 extension installs. The largest contributor to secrets leakage was the bundling by developers of hidden files, also known as dotfiles, says the report. The quantity of .env files was especially prominent, although hardcoded credentials in extension source code were also prevalent."

Over 550 validated secrets were found across more than 500 Visual Studio extensions from hundreds of extension publishers. The leaked secrets included AI provider API keys for OpenAI, Gemini, Anthropic, xAI, DeepSeek, HuggingFace, and Perplexity; platform credentials for AWS, GitHub, Stripe, Auth0, and Google Cloud Platform; and database secrets for MongoDB, Postgres, and Supabase. Over 100 valid Azure DevOps personal access tokens and over thirty OVSX access tokens were identified, representing install bases of over 85,000 and 100,000 installs respectively. The main cause was bundling hidden files (dotfiles), especially .env files, plus hardcoded credentials in source code. Secrets also leaked via AI configuration files, build configurations like package.json, and README.md. Microsoft and Wiz launched a notification campaign to alert impacted publishers.

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