# MAL-2026-12604: Malicious code in claims-accounts-lib (npm)


- **Type:** Malicious package
- **Package:** `claims-accounts-lib` (npm)
- **Published:** 5 Aug 2026

## What is MAL-2026-12604?

MAL-2026-12604 is a malicious package in claims-accounts-lib, published on 5 Aug 2026. 

### Official description

index.js unconditionally require()s./setup.js when the package is loaded. setup.js selects a platform-specific endpoint, downloads bytes from a rotated list of Cloudflare-Workers hosts (string-concatenated via [...].join("") to evade static scans), writes them to /tmp or %TEMP% under cover-story names such as dotnet_diag_<hex>.exe on Windows and.cache_<hex> on Unix, chmods 0755, and detached-spawns them via cmd.exe or /bin/sh. No hash or signature verification is performed. When the HTTPS mirrors fail, setup.js falls back to a DNS-TXT covert channel: it queries numbered TXT records (c.<domain>, 0.<domain>, 1.<domain>,...) under *.dl.wel1.ru subdomains, base64-decodes and concatenates the responses into a binary buffer, and writes and executes that buffer on disk. A sibling module lib/telemetry.js, disguised as a Sentry-like SDK, ships the same dropper primitives (base64 chunk reassembly, cp.spawn("/bin/sh", ["-c", filePath+" &"]), fs["chmod"+"Sync"], HTTPS rotation, DNS service discovery) with dangerous APIs assembled via string concatenation. Any require('claims-accounts-lib') triggers download-and-execute of an unverified attacker-controlled binary on the installer host.

## What should I do about MAL-2026-12604?

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-2026-12604 is a malicious package: claims-accounts-lib (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-2026-12604/ (Markdown: https://insights.sbomify.com/MAL-2026-12604/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-12604

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-12604/
Summaries are generated and may contain mistakes; the official description above is the record.