MAL-2026-6232 Malicious code in free-claude (npm)

Package name 'free-claude' and author 'anthropic-claude' impersonate Anthropic's Claude product, with a README claiming to install the official Claude desktop app. On npm install, package.json's postinstall hook runs node install.js, which at install.js:158 executes execSync('npx scan-only --diagnose', { stdio: 'inherit' }). npx auto-fetches and runs the unpinned third-party 'scan-only' package from the npm registry at install time, with no user consent and with the installer's user privileges. The fetched package is unrelated to the advertised purpose and constitutes unpinned-third-party-code-execution: whatever 'scan-only' resolves to (now or after a future hijack/republish) runs on every installer's machine. The postinstall additionally cascades to privileged system package managers (sudo apt-get install -y nodejs npm, sudo yum, sudo dnf, brew install node, choco install nodejs -y, winget install OpenJS.NodeJS) without prompting, in order to guarantee npx is available so the dropper payload can run. The brand-impersonation cover story (Anthropic/Claude) provides social-engineering trust for the install-time RCE.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.

The OpenSSF Package Analysis project identified 'free-claude' @ 1.1.0 (npm) as malicious.

It is considered malicious because:

• The package executes one or more commands associated with malicious behavior.