MAL-2026-12560 Malicious code in checkout-desktop-promocode (npm)
Malicious package
Published
MAL-2026-12560 is a malicious package: checkout-desktop-promocode (npm). Every version was published to cause harm.
Task:
1. Search this repository's dependency manifests and lockfiles for the package, including transitive dependencies.
2. If it is present, remove it, regenerate the lockfile with the project's package manager, and replace whatever it was used for.
3. List any CI runners, developer machines or containers that installed it, so their secrets can be rotated.
4. If the package is not used anywhere, say so and change nothing.
Reference: https://insights.sbomify.com/MAL-2026-12560/ (Markdown: https://insights.sbomify.com/MAL-2026-12560/index.md)
- Package
- checkout-desktop-promocode
- Registry
- npm
What is MAL-2026-12560?
MAL-2026-12560 is a malicious package in checkout-desktop-promocode, published on 5 Aug 2026.
Official description
On require() of checkout-desktop-promocode, index.js loads vendor.js which selects a per-platform endpoint, downloads a binary over HTTPS from obfuscated author-controlled hosts (sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, net.dl.wel1.ru, and oob-worker.cf*-*.workers.dev), with a DNS-TXT chunked base64 covert-channel fallback. The fetched bytes are written to /tmp or %TEMP% under an innocuous filename (.cache<rand> or dotnet_diag_<rand>.exe), chmod 0755'd, and spawned detached via /bin/sh -c or cmd.exe. C2 hostnames are assembled at runtime by Array.join on fragment arrays (e.g. ["oob-worker.cf99-9b3.w","orker","s.d","ev"].join("")) to evade static string scanners, and log calls are stubbed to a no-op writer. The package advertises itself as a promocode SDK but ships none of that functionality; the only effect of importing it is arbitrary attacker code execution on the installer's host.
What should I do about MAL-2026-12560?
Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.