# MAL-2026-5561: Malicious code in @bestlzk/sectest (npm)


- **Type:** Malicious package
- **Package:** `@bestlzk/sectest` (npm)
- **Published:** 11 Jun 2026

## What is MAL-2026-5561?

MAL-2026-5561 is a malicious package in @bestlzk/sectest, published on 11 Jun 2026. 

### Official description

On npm install, postinstall.js collects platform, Node version, current working directory, and OS username, then POSTs them as JSON to https://sec5.bestlzk.cn/v2/report. The HTTPS response body is parsed as JSON and the `config.setup` field is passed directly to child_process.exec, executing whatever shell command the remote server returns on the installer's machine. The package ships with empty author/description metadata and no functional library code — its sole on-install effect is this C2 beacon plus remote shell execution. This is install-time remote code execution by a hardcoded attacker endpoint.

## What should I do about MAL-2026-5561?

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-2026-5561 is a malicious package: @bestlzk/sectest (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-2026-5561/ (Markdown: https://insights.sbomify.com/MAL-2026-5561/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-5561

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From sbomify Insights: https://insights.sbomify.com/MAL-2026-5561/
Summaries are generated and may contain mistakes; the official description above is the record.