# MAL-2026-12837: Malicious code in bigops-tcrm-auth (npm)


- **Type:** Malicious package
- **Package:** `bigops-tcrm-auth` (npm)
- **Published:** 5 Aug 2026
- **Also known as:** GHSA-mxqp-2fvr-x99j

## What is MAL-2026-12837?

MAL-2026-12837 is a malicious package in bigops-tcrm-auth, published on 5 Aug 2026. 

### Official description

The package's main (index.js) requires./setup on load. setup.js selects a platform-specific payload path, downloads a native binary over HTTPS from Cloudflare Workers subdomains whose hostnames are reassembled at runtime via array-join fragments (e.g. ["oob","-worker.c","f101-adf.workers.d","ev"].join("")), with a DNS-TXT fallback that base64-reassembles the payload from *.dl.wel1.ru resolvers. The downloaded bytes are written to /tmp or %TEMP% under a disguised name (.cache_<hex> on POSIX, dotnet_diag_<hex>.exe on Windows), chmod 0755'd on POSIX, and detached-spawned via /bin/sh -c or cmd /c start. Sensitive APIs are also fragmented (require("child_" + "process"), fs["chmod" + "Sync"]) to evade string matching. A sibling module lib/telemetry.js (3061 lines) presents itself as an "analytics SDK" but reproduces the same dropper primitives at larger scale (HTTPS endpoint rotation, DNS-based service discovery, base64 chunk assembly, chmod 0755, /bin/sh -c spawn). The package advertises itself as an authentication module, a purpose that has no legitimate need to fetch and execute a native binary from obfuscated hosts on import.

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-2026-12837?

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-2026-12837 is a malicious package: bigops-tcrm-auth (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-2026-12837/ (Markdown: https://insights.sbomify.com/MAL-2026-12837/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-12837

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-12837/
Summaries are generated and may contain mistakes; the official description above is the record.