Which versions of anthropic-setup are malicious?

The following npm versions of anthropic-setup are flagged malicious: 1.0.1. Treat any of these as compromised.

How do I remediate anthropic-setup if I installed it?

Remove anthropic-setup 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.

I already installed anthropic-setup — how do I know if it already compromised me?

If anthropic-setup 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.

Is anthropic-setup part of a known attack campaign?

Yes — anthropic-setup is associated with the IN-MAL-2026-014938 campaign. Packages in the same campaign often share infrastructure and payloads, so check whether any related packages are also in your dependency tree.

How do I find anthropic-setup across my projects, lockfiles, and CI pipelines?

Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for anthropic-setup (version 1.0.1). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging anthropic-setup across your stack and pipelines.

Malicious package

anthropic-setupnpm

anthropic-setup is a confirmed malicious npm package (MAL-2026-12510) that executes malicious code on install (malicious version 1.0.1). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in anthropic-setup (npm)

MAL-2026-12510

Immediate action

Remove the package, then rotate any secrets the build/runtime could reach.

npm uninstall anthropic-setup

What this malware does

The package presents itself as an Anthropic API setup helper but writes ~/.claude/settings.json with ANTHROPIC_BASE_URL set to https://sugarball.vercel.app and stores the user-supplied ANTHROPIC_API_KEY (passed as argv[2] to npx anthropic-setup) alongside an apiKeyHelper echoing that key. Because the configured base URL is not api.anthropic.com, every subsequent Claude CLI invocation transmits the installer's Anthropic API key and full prompt/response content to sugarball.vercel.app, a third-party Vercel deployment. The bin.js entrypoint is a single eval(Buffer.from('...','base64').toString('utf8')) that decodes to the same hijack logic shown in index.js, concealing the attacker-controlled destination from casual registry inspection.

Malicious versions

1 flagged

1.0.1

Indicators of compromise (SHA-256)

9a5019e390fffd163e88f49fe1fc12c4ce8d2e50d7563cf7cf0a38508dc4eef5

Detection & response playbook

Malicious package

Find it
Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for anthropic-setup (version 1.0.1). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging anthropic-setup across your stack and pipelines.
If you installed it — respond
Remove anthropic-setup 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.
Did it already run?
If anthropic-setup 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 anthropic-setup 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. anthropic-setup on npm has been identified as a malicious package (version 1.0.1 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-014938

References

npmjs.com

Credits

Amazon Inspector · finder

Detect & block this

O3 blocks anthropic-setup-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.

Malware detection Runtime egress monitoring

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