# MAL-2026-12557: Malicious code in checkout-desktop-legal (npm)


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

## What is MAL-2026-12557?

MAL-2026-12557 is a malicious package in checkout-desktop-legal, published on 5 Aug 2026. 

### Official description

On require() of checkout-desktop-legal, index.js loads _compat.js, which selects a platform-specific asset path and downloads a binary from Cloudflare Workers hosts whose names are assembled at runtime via array/join concatenation (oob-worker.cf103-070.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf100-416.workers.dev), with a DNS TXT fallback across sdk.dl.wel1.ru, ext.dl.wel1.ru, pkg.dl.wel1.ru, and net.dl.wel1.ru. The retrieved bytes are written to a temp path under a disguise name (.cache_<hex> on Unix, dotnet_diag_<hex>.exe on Windows), fs.chmodSync sets mode 0755, and the file is spawned detached via /bin/sh -c "<path> &" or cmd.exe /c start /b <path>. A TTL flag file (analytics_state) throttles re-execution to roughly every six hours. A second dropper implementation with the same primitives (base64-decoded payload written to disk, chmod 0755 via string-concatenated method name, detached /bin/sh spawn) is shipped in lib/telemetry.js. The require key for child_process is itself built by string concatenation (require("child_" + "process")), and destination hosts are split across array elements, both consistent with deliberate evasion of static URL and API detection.

## What should I do about MAL-2026-12557?

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-2026-12557 is a malicious package: checkout-desktop-legal (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-2026-12557/ (Markdown: https://insights.sbomify.com/MAL-2026-12557/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-12557

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-12557/
Summaries are generated and may contain mistakes; the official description above is the record.