studiocode_tools

GHSA-j79g-9wmp-mcv8

Malicious code in studiocode_tools (npm)

Details

**Severity:** Critical

**Affected versions:** `= 1.0.1`

## Source: amazon-inspector (261d413c0847b530c9a452c209c25e0a7d9123f9b0f20b26d0afcc41a929c74a)
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.

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Credit: [OpenSSF](https://github.com/ossf/malicious-packages) ([source](https://github.com/ossf/malicious-packages/blob/ae1ef40954ea15dd560720d58f647c9880afc699/osv/malicious/npm/studiocode_tools/MAL-2026-17523.json))

**References:**
- https://github.com/ossf/malicious-packages/blob/ae1ef40954ea15dd560720d58f647c9880afc699/osv/malicious/npm/studiocode_tools/MAL-2026-17523.json
- https://www.npmjs.com/package/studiocode_tools/v/1.0.1
- https://github.com/advisories/GHSA-j79g-9wmp-mcv8

Compromised versions (1)

= 1.0.1

Any computer that installed or ran a compromised version should be considered fully compromised. Rotate every secret on that machine from a clean environment.