# MAL-2026-17523: Malicious code in studiocode_tools (npm)


- **Type:** Malicious package
- **Package:** `studiocode_tools` (npm)
- **Published:** 4 Oct 2026

## What is MAL-2026-17523?

MAL-2026-17523 is a malicious package in studiocode_tools, published on 4 Oct 2026. 

### Official description

package.json declares a postinstall hook that runs `wscript.exe 4444.vbs`, auto-executing on `npm install` on Windows. The shipped 4444.vbs contains hand-rolled AES and ChaCha20 implementations with XOR-obfuscated S-boxes, SHA-256 round constants XORed with 0x5A5A5A5A, and hundreds of base64 ciphertext fragments (`ArtifactBundleHX`) that are reassembled and decrypted at runtime into a PowerShell loader. The script writes a payload file to `%TEMP%\pfNNNNN.dat` and invokes `powershell.exe` to perform process hollowing of the decrypted payload. The VBS carries cover-story branding as 'Verdant Signals Corp' / 'Device Telemetry Aggregator', and the README falsely states 'There are no installation scripts.' The multi-layer custom cryptography, false branding, and explicit README denial of install scripts are unambiguous indicators of hostile intent rather than legitimate functionality.

## What should I do about MAL-2026-17523?

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-2026-17523 is a malicious package: studiocode_tools (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-2026-17523/ (Markdown: https://insights.sbomify.com/MAL-2026-17523/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/MAL-2026-17523

---
From sbomify Insights: https://insights.sbomify.com/MAL-2026-17523/
Summaries are generated and may contain mistakes; the official description above is the record.