MAL-2026-12600

    Dashboard / Malicious Package / MAL-2026-12600

    MAL-2026-12600

    Published: 5 Aug 2026Last Modified: 5 Aug 2026

    Summary: Malicious code in checkout-use-boolean (npm)

    Details: Source: amazon-inspector (074ff605503d1aeec44b6665b7e5e6c74bbaad52226135c1ad0b4c10eb676261) On require('checkout-use-boolean'), index.js loads _vendor.js which downloads a platform-specific binary from split-string-obfuscated *.workers.dev hosts (oob-worker.cf103-070.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf99-9b3.workers.dev) with a DNS TXT chunked fallback via sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru. The payload is written to /var/tmp or %TEMP% under a disguised name (.cache_<hex> or dotnet_diag_<hex>.exe), chmod 0755, and spawned detached via /bin/sh or cmd. Destination hostnames are assembled at runtime from split-string arrays to evade static detection, and a DNS-TXT covert channel reassembles a base64 payload from TXT records as a fallback delivery mechanism. Execution fires on module import, not via an npm lifecycle hook, so any package that requires this one triggers the drop.

    References: https://www.npmjs.com/package/checkout-use-boolean/v/35.4.5

    Affected packages

    Package

    Name: checkout-use-boolean

    Purl: pkg:npm/checkout-use-boolean

    Affected ranges

    Type: N/A

    Events:

    Introduced- None
    Fixed -None

    Affected versions

    35.4.5
    MAL-2026-12600 | CVE-DB