Supply chain · npm · High

Critical Malicious npm Package 'nebulaai-sdk' Delivers Windows Executable

Threat Engine Auto-Feed · data current as of 2026-09-28

The npm package `nebulaai-sdk` version 1.0.0 contains malicious code that executes a Windows PE executable during installation. This leads to arbitrary code execution and establishes a persistent, masqueraded binary with potential command-and-control capabilities on affected Windows systems. Organizations using this package are at risk of system compromise.

  • Package: npm / nebulaai-sdk
  • Affected versions: = 1.0.0
  • Severity: critical
  • Reach: ~175/wk
  • Exposure: 70/100 (High)

What happened — Malicious package

The npm package `nebulaai-sdk` version 1.0.0 includes a `preinstall.js` script designed to execute during the package installation process. This script decodes a base64+zlib-encoded Windows PE executable, writes it to `%LOCALAPPDATA%\Microsoft\Conhost\conhost.exe`, and then silently spawns it. The executable appears to establish remote command-and-control functionality.

How the attack works

This is a supply-chain attack where a malicious package is published to a public registry. When a developer or automated system installs the package, a pre-installation script is triggered. This script then deploys and executes a payload on the host system, achieving arbitrary code execution and potentially establishing persistence and external communication without user interaction or visible indicators.

Who's exposed

Profiles most at risk

  • Development teams using the npm ecosystem, particularly those building on Windows environments.
  • CI/CD pipelines configured to pull and install npm packages on Windows build agents.
  • Any system where `nebulaai-sdk` version 1.0.0 was installed on a Windows operating system.

Conditions that increase exposure

  • Installing `nebulaai-sdk` version 1.0.0 directly or as a transitive dependency.
  • Lack of package lockfiles (e.g., `package-lock.json`) or unpinned dependency versions allowing the malicious version to be pulled.
  • Using internal package mirrors that have synchronized the malicious version.
  • Running `npm install` on Windows hosts.

Blast-radius scenarios

  • An attacker gains arbitrary code execution under the privileges of the installing user on a Windows system.
  • A persistent, masqueraded binary is staged on the compromised system, potentially enabling long-term access.
  • The compromised system may attempt to establish communication with an external command-and-control server, indicating potential data exfiltration or further malicious activity.

What to do (defensive)

Detect

  • Scan `package.json` and `package-lock.json` files for direct or transitive dependencies on `nebulaai-sdk` version 1.0.0.
  • Monitor for the creation of `conhost.exe` in `%LOCALAPPDATA%\Microsoft\Conhost\` on Windows systems.
  • Inspect network traffic for connections to `65.87.7.132` from development or build environments.
  • Review `npm install` logs for execution of `preinstall.js` scripts, especially for `nebulaai-sdk`.

Contain

  • Immediately quarantine any Windows systems identified as having installed `nebulaai-sdk` version 1.0.0.
  • Block network communication to `65.87.7.132` at the perimeter and host level.
  • Remove `nebulaai-sdk` version 1.0.0 from all package registries, caches, and build environments.
  • Implement strict dependency pinning and review changes to `package-lock.json` files.

Remediate

  • Remove `nebulaai-sdk` version 1.0.0 from all project dependencies.
  • Perform a full forensic analysis on any Windows systems where the package was installed to identify the extent of compromise and remove the malicious `conhost.exe`.
  • Rebuild affected systems from trusted images if compromise cannot be fully remediated.
  • Rotate credentials for any services or users that may have been exposed on compromised systems.

Frontier verdict — High

Prioritize immediate detection and removal of `nebulaai-sdk` version 1.0.0 from all Windows-based npm environments due to critical arbitrary code execution and C2 implications.

Sources

For detection-engineering and awareness only · point-in-time · not security advice · sourced from the GitHub Advisory Database.