npm · Malicious package advisory
Malwarestudiocode_tools
MAL-2026-17523
Malicious code in studiocode_tools (npm)
Details
--- _-= Per source details. Do not edit below this line.=-_ ## 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.
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.