# MAL-2026-12410: Malicious code in pfp-block-mobile-steps (npm)


- **Type:** Malicious package
- **Package:** `pfp-block-mobile-steps` (npm)
- **Published:** 5 Aug 2026
- **Also known as:** GHSA-627r-73p5-f9mm

## What is MAL-2026-12410?

MAL-2026-12410 is a malicious package in pfp-block-mobile-steps, published on 5 Aug 2026. 

### Official description

On require of the package, index.js unconditionally loads _shim.js, which selects a payload path based on process.platform/arch (linux_x64, linux_arm64, darwin, win32) and downloads an opaque binary from one of four hardcoded Cloudflare Workers hosts (oob-worker.cf99-9b3.workers.dev, oob-worker.cf100-416.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf102-baf.workers.dev). Endpoint hostnames are assembled at runtime from string fragments joined together to defeat static analysis. If HTTPS retrieval fails, a fallback path uses DNS TXT record lookups against *.dl.well1.site (reading a chunk count from c.<domain> then reassembling base64 payload from numbered TXT records) to deliver the same executable out-of-band. The fetched bytes are written to a temp path under a stealth filename (dotnet_diag_*.exe,.cache_*), chmod 0755 on Unix, and spawned detached via /bin/sh -c or cmd /c start /b with stderr silenced. No hash or signature verification is performed, and no build/runtime purpose in a 'platform adapter' package requires this. A run-once flag file and opt-out environment variables gate re-execution, consistent with anti-analysis behavior.

Any computer that has this package installed or running should be considered fully compromised. All secrets and keys stored on that computer should be rotated immediately from a different computer. The package should be removed, but as full control of the computer may have been given to an outside entity, there is no guarantee that removing the package will remove all malicious software resulting from installing it.

## What should I do about MAL-2026-12410?

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-2026-12410 is a malicious package: pfp-block-mobile-steps (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-2026-12410/ (Markdown: https://insights.sbomify.com/MAL-2026-12410/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-12410

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-12410/
Summaries are generated and may contain mistakes; the official description above is the record.