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Malicious package

claude-content-writernpm

Malicious code in claude-content-writer (npm) Remove it immediately and rotate any exposed credentials.

MAL-2026-4524
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall claude-content-writer

What this malware does

On npm install, the package's postinstall hook runs scripts/install-dependencies.sh, which performs git clone --depth 1 https://github.com/AgriciDaniel/claude-seo.git and git clone of github.com/blader/humanizer into ~/.claude/skills with no commit pinning, then cd claude-seo && bash install.sh. The cloned repositories are personal GitHub accounts unrelated to the package publisher; whatever code their maintainers (or an attacker who takes over either account) push to HEAD will execute on every installer's machine at install time. There is no integrity verification, version pinning, or publisher-matching for the fetched code. Additionally, package.json declares the package itself as a dependency (claude-content-writer: ^2.0.1), which expands the install-time trust surface unpredictably by pulling another published version of the same package during resolution.

Malicious versions

1 flagged
2.2.0

Indicators of compromise (SHA-256)

b38e69b148dc7998c9ab02fb5b6c2a90413a88129cf7db96b1c900e9c830f719

Detection & response playbook

Malicious package
  1. Find it

    Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for claude-content-writer (version 2.2.0). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging claude-content-writer across your stack and pipelines.

  2. If you installed it — respond

    Remove claude-content-writer from your project and lockfile, then assume any secrets accessible to the build or runtime were exposed: rotate API keys, tokens, and credentials, and audit for unexpected outbound activity or persistence.

  3. Did it already run?

    If claude-content-writer 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.

  4. How O3 protects you

    O3 blocks claude-content-writer 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

No. claude-content-writer on npm has been identified as a malicious package (version 2.2.0 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-004037

References

Credits

  • Amazon Inspector · finder

Detect & block this

O3 blocks claude-content-writer-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.

claude-content-writer (npm) malicious package — MAL-2026-4524 | O3 Security