A new variant of the Shai-Hulud npm worm, dubbed ChainDrop, has compromised hundreds of software packages and introduced stealthier ways to spread. It matters because it can infect developers’ projects and automated build systems without leaving obvious malicious changes in source-code repositories, making routine reviews less effective.

Researchers identified the attack on 4 August, finding 444 affected packages from multiple publishers with combined monthly downloads of about two billion; targets included keyv, flat-cache and cache-manager. ChainDrop steals npm, GitHub and cloud credentials, then modifies package tarballs and adds VS Code or Claude Code configuration hooks that can run when an infected branch is opened. It can use stolen npm tokens to republish altered packages and GitHub access to commit malicious configuration files across accessible repositories and branches.