# MAL-2026-12588: Malicious code in checkout-promocode-logic (npm)


- **Type:** Malicious package
- **Package:** `checkout-promocode-logic` (npm)
- **Published:** 5 Aug 2026

## What is MAL-2026-12588?

MAL-2026-12588 is a malicious package in checkout-promocode-logic, published on 5 Aug 2026. 

### Official description

On require, index.js loads _ext.js which selects a per-OS payload path, fetches an executable over HTTPS from string-concatenation-obfuscated hosts (oob-worker.cf100-416.workers.dev, oob-worker.cf102-baf.workers.dev, oob-worker.cf99-9b3.workers.dev, oob-worker.cf103-070.workers.dev) with a DNS-TXT covert-channel fallback that reassembles base64 chunks from TXT records under sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru, writes the bytes to /var/tmp/.cache_<rand> (or %TEMP%\dotnet_diag_<rand>.exe on Windows), chmods 0755, and spawns the file detached via /bin/sh -c or cmd.exe /c start /b. Destination hosts, DNS fallback zones, the child_process module name, and dropped file names are all assembled from split string fragments at runtime, and the dropped file is named to masquerade as a.NET diagnostic or telemetry artifact. lib/telemetry.js ships the same dropper primitives with stronger evasion (require("child_" + "process"), fs["chmod" + "Sync"], base64-chunk reassembly).

## What should I do about MAL-2026-12588?

Remove the package from your dependencies and lockfiles, then rotate any secrets on machines where it was installed.

## Fix prompt for AI coding agents

```text
MAL-2026-12588 is a malicious package: checkout-promocode-logic (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-2026-12588/ (Markdown: https://insights.sbomify.com/MAL-2026-12588/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-12588

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-12588/
Summaries are generated and may contain mistakes; the official description above is the record.