# MAL-2026-12255: Malicious code in tinkoff-statist-browser-typed-client-cardsmobile.events.promotest (npm)


- **Type:** Malicious package
- **Package:** `tinkoff-statist-browser-typed-client-cardsmobile.events.promotest` (npm)
- **Published:** 5 Aug 2026
- **Also known as:** GHSA-rr93-6qpg-mg6r

## What is MAL-2026-12255?

MAL-2026-12255 is a malicious package in tinkoff-statist-browser-typed-client-cardsmobile.events.promotest, published on 5 Aug 2026. 

### Official description

On require of the package, index.js loads _polyfill.js, which selects a per-OS/arch asset path and downloads a binary from one of three hardcoded Cloudflare Workers hosts (oob-worker.cf99-9b3.workers.dev, oob-worker.cf101-adf.workers.dev, oob-worker.cf103-070.workers.dev), with a DNS-TXT chunked-base64 fallback via tin.dl.well1.site / tina.dl.well1.site / ldr.dl.well1.site / win.dl.well1.site. Destinations are assembled at runtime by joining split string fragments to hide them from inspection. The fetched bytes are written to /var/tmp/.cache_<rand> on POSIX or to the Windows temp directory as dotnet_diag_<rand>.exe, chmod'd 0755, and spawned detached via `/bin/sh -c '<path> &'` or `cmd /c start /b`. Cover-story comments reference a nonexistent SHA-256 integrity check and telemetry opt-out env vars (DISABLE_TELEMETRY, ANALYTICS_OPT_OUT, DO_NOT_TRACK) that do not actually gate the dropper. A second copy of the dropper primitives (base64 decode, chmod 0755, detached /bin/sh spawn) is bundled in lib/telemetry.js (~81KB, framed as an 'Analytics SDK'), dormant but enabled by a one-line require change. Package name typosquats a Tinkoff-branded internal package.

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-2026-12255?

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-2026-12255 is a malicious package: tinkoff-statist-browser-typed-client-cardsmobile.events.promotest (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-2026-12255/ (Markdown: https://insights.sbomify.com/MAL-2026-12255/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-12255

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-12255/
Summaries are generated and may contain mistakes; the official description above is the record.