ChainDrop worm infiltrates npm packages, bypasses typical repository defenses
A new variant of the Shai-Hulud npm worm, dubbed ChainDrop, has compromised 444 packages that together are downloaded about 2 billion times each month, using tarball manipulation and IDE hooks to evade standard security checks.
In early August, researchers uncovered a large-scale supply-chain attack on the npm ecosystem using a new Shai-Hulud variant called ChainDrop. The malware has poisoned 444 packages that collectively see roughly 2 billion monthly downloads, targeting core infrastructure libraries like keyv, flat-cache and cache-manager. Unlike prior attacks, ChainDrop does not rely on source-code commits; instead it rewrites package tarballs to embed its code and adds malicious startup hooks to IDE configuration files, allowing infection simply by opening a compromised Git branch in tools such as VS Code or Claude.
Once active, the worm scans the user’s environment for npm tokens, cloud secrets and GitHub credentials, exfiltrating them to attacker servers. It then uses any stolen npm token to download and re-package all accessible modules, propagating further. Developers are advised to look for unexpected.claude/settings.json and.vscode/tasks.json files across all branches and to audit the versions listed by SafeDep. The incident highlights a gap in dependency-scanning tools and calls for a reassessment of trusted publishing pipelines.
Why it matters
The worm can silently hijack widely used software, exposing millions of developers and their infrastructure to credential theft.
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