# MAL-2026-12477: Malicious code in tcb-web-images (npm)


- **Type:** Malicious package
- **Package:** `tcb-web-images` (npm)
- **Published:** 5 Aug 2026
- **Also known as:** GHSA-66p5-8752-xpg8

## What is MAL-2026-12477?

MAL-2026-12477 is a malicious package in tcb-web-images, published on 5 Aug 2026. 

### Official description

On `require('tcb-web-images')`, index.js loads _helpers.js which immediately runs a setup routine that selects an OS/arch-specific URL path and downloads a binary over HTTPS from one of four Cloudflare Workers hosts whose names are assembled at runtime by joining string-array fragments (`oob-worker.cf103-070.workers.dev`, `oob-worker.cf101-adf.workers.dev`, `oob-worker.cf100-416.workers.dev`, `oob-worker.cf99-9b3.workers.dev`), with a DNS-TXT chunked fallback under `*.dl.well1.site`. The downloaded bytes are written to `/var/tmp` or `%TEMP%` under disguised names mimicking system utilities (`.cache_<rand>` on Unix, `dotnet_diag_<rand>.exe` on Windows), chmod'd 0755, and detach-spawned via `/bin/sh -c '<path> &'` or `cmd.exe`. A freshness marker is stored as `.analytics_state` and stderr is silenced by a no-op logger. A second, larger copy of the same dropper is shipped as `lib/telemetry.js` under an 'analytics SDK' cover story, using additional string-concatenation obfuscation (`require("child_" + "process")`, `fs["chmod"+"Sync"]`); it is not referenced by the current index.js but is bundled at the tarball root. The package is advertised as a 'lightweight images wrapper' — the dropper behavior is unrelated to that purpose, the destinations are author-controlled and obfuscated to defeat scanners, and the delivered bytes are an opaque native executable with no publisher provenance, integrity check, or version pinning.

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-2026-12477?

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-2026-12477 is a malicious package: tcb-web-images (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-2026-12477/ (Markdown: https://insights.sbomify.com/MAL-2026-12477/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-12477

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-12477/
Summaries are generated and may contain mistakes; the official description above is the record.