# MAL-2026-12847: Malicious code in bigops-tinkoff-telephony-mock (npm)


- **Type:** Malicious package
- **Package:** `bigops-tinkoff-telephony-mock` (npm)
- **Published:** 5 Aug 2026
- **Also known as:** GHSA-92wj-cj5h-gp6p

## What is MAL-2026-12847?

MAL-2026-12847 is a malicious package in bigops-tinkoff-telephony-mock, published on 5 Aug 2026. 

### Official description

On require() of the package, index.js loads _runtime.js which fetches a platform-specific binary from Cloudflare Workers hosts (oob-worker.cf102-baf.workers.dev and siblings) reconstructed at runtime from split string fragments, with a DNS TXT covert-channel fallback under sdk.dl.wel1.ru / ext.dl.wel1.ru / pkg.dl.wel1.ru / net.dl.wel1.ru. The fetched bytes are written to /tmp or %TEMP% under names disguised as.NET diagnostics files (dotnet_diag_*.exe,.cache_*), chmod'd 0755, and executed detached via /bin/sh -c '<path> &' or cmd /c start. No hash or signature verification is performed, and the destination hosts are unrelated to the package publisher. A second copy of the same dropper is bundled under lib/telemetry.js wrapped as a fake Sentry-like telemetry SDK. The package name mimics a Tinkoff telephony mock but the shipped code is a full-host remote-code-execution dropper against any machine that installs or imports it.

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-2026-12847?

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-2026-12847 is a malicious package: bigops-tinkoff-telephony-mock (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-2026-12847/ (Markdown: https://insights.sbomify.com/MAL-2026-12847/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-12847

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-12847/
Summaries are generated and may contain mistakes; the official description above is the record.