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Malicious package

@antstackio/eslint-config-antstacknpm

Malicious code in @antstackio/eslint-config-antstack (npm) Remove it immediately and rotate any exposed credentials.

MAL-2025-191187
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall @antstackio/eslint-config-antstack

What this malware does

The package @antstackio/eslint-config-antstack was found to contain malicious code.

This package was compromised by the Sha1-Hulud: The Second Coming NPM worm. The malicious payload steals tokens and credentials and publishes them to GitHub. The worm will propogate itself to NPM packages the user owns and establish persistence is a GitHub action. The package may also destroy the user's home directory.

Malicious versions

1 flagged
0.0.3

Indicators of compromise (SHA-256)

9cef6b06b4f6b5856fb26d1d823db7d7f92e0f37bcd85edd0a6ebe0bead3c9eb
df3b34f284b315d21cd0f6b7ea57e1fc8b908ade13ffde115d3fb1f6727c7d4a

Detection & response playbook

Credential / info stealer
  1. Find it

    Scan your lockfiles (package-lock.json, pnpm-lock.yaml, yarn.lock, requirements.txt, poetry.lock, etc.) and build artifacts for @antstackio/eslint-config-antstack (version 0.0.3). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging @antstackio/eslint-config-antstack across your stack and pipelines.

  2. If you installed it — respond

    @antstackio/eslint-config-antstack is built to steal secrets, so assume every credential the build or runtime could read is compromised. Remove it from your project and lockfile, then rotate ALL exposed secrets — npm/registry tokens, cloud keys, CI/CD secrets, SSH keys, and any .env values — from a known-clean machine. Audit logs for unauthorized use of those credentials.

  3. Did it already run?

    If @antstackio/eslint-config-antstack 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 @antstackio/eslint-config-antstack 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. @antstackio/eslint-config-antstack on npm has been identified as a malicious package (version 0.0.3 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

References

Credits

  • Amazon Inspector · finder

Detect & block this

O3 blocks @antstackio/eslint-config-antstack-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.

@antstackio/eslint-config-antstack (npm) malicious package — MAL-2025-191187 | O3 Security