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Malicious package

checkout-public-tokensnpm

checkout-public-tokens is a confirmed malicious npm package (MAL-2026-12589) that steals credentials and exfiltrates sensitive data (malicious version 35.4.9). Do not install it — remove it immediately and rotate any exposed credentials.

Malicious code in checkout-public-tokens (npm)

MAL-2026-12589
Immediate action
Remove the package, then rotate any secrets the build/runtime could reach.
npm uninstall checkout-public-tokens

What this malware does

On require() of checkout-public-tokens, index.js loads platform.js which downloads an opaque binary payload from hardcoded string-split-obfuscated hosts (oob-worker.cf103-070.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf101-adf.workers.dev), with a DNS-TXT base64 fallback resolver via sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, and net.dl.wel1.ru. The payload is written to /tmp or %TEMP% under a disguised name (.cache<hex> or dotnet_diag_<hex>.exe), chmodded to 0755, and spawned detached via /bin/sh -c or cmd.exe /c start /b. Destination hostnames are constructed at runtime by joining split literals, and in-file comments frame the download-and-execute chain as telemetry, analytics, and cache validation. The package advertises itself as a token utility; the hosts and behavior are unrelated to any documented purpose and there is no hash or signature verification of the fetched bytes.

Malicious versions

1 flagged
35.4.9

Indicators of compromise (SHA-256)

c1ca81222c080449cad71d071579738ea810e280c6e8ed3b53647efdde902536

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 checkout-public-tokens (version 35.4.9). O3 Security's supply-chain scanner checks every dependency against known-malicious package intelligence at install time and in CI, flagging checkout-public-tokens across your stack and pipelines.

  2. If you installed it — respond

    checkout-public-tokens 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 checkout-public-tokens 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 checkout-public-tokens 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. checkout-public-tokens on npm has been identified as a malicious package (version 35.4.9 flagged). It should be removed immediately — do not install or keep it in your dependency tree.

Campaign

IN-MAL-2026-015188

References

Credits

  • Amazon Inspector · finder

Detect & block this

O3 blocks checkout-public-tokens-class packages before install and in CI — and if it already ran, its runtime egress monitoring catches the credential exfiltration and severs the channel.

Explore

checkout-public-tokens (npm) malicious package — MAL-2026-12589 | O3 Security