As software development processes grew, attackers’ focus began to shift from applications to developers’ computers, CI/CD pipelines, and dependency chains. One of the most striking examples of this new generation of threats is the Shai-Hulud class supply-chain attacks.

In this article, I explain the basic principles of the attack, why it is extremely dangerous, and a practical defense approach that modern software teams can apply against such risks. In addition, the scripts and security automation mechanisms used in this context are shared as examples at the end of the article.

🎯 What is the Shai-Hulud Attack?

Shai-Hulud is a supply-chain attack that infiltrates developers’ local environments, access keys, and CI/CD processes using the dependency loading mechanism.

The attack typically proceeds as follows:

1) Release of malicious package version

The attacker spoofs the name of a popular package using a hijacked NPM maintainer account or typo-squatting method.

2) Automatic execution of malicious script during `npm install`

While installing NPM packages, lifecycle scripts such as install, postinstall, prepare are automatically triggered. The attacker uses this natural behavior to inject code into the system.

3) Collection of critical information on the machine

The malicious script can collect the following data:

Environment variables (ENV)
Git access tokens
SSH private keys
Cloud provider credentials
CI/CD access tokens
Local setting files

4) Transmission of collected information to the attacker

In some variants, the attacker creates a seemingly ordinary repo in the victim’s Git account and uploads data there. For example, seemingly innocent files like environment.json may actually contain leaked credentials.

5) Chain effect

With this information, the attacker:

Can hijack CI/CD pipelines
Docker can push/pull registries
Can access Kubernetes cluster management
May release malicious versions of other packages
Can gain permanent access in production environments

Therefore, this attack is a major risk that can spread from a single developer to the entire organization.

⚠️ Critical Note: Local Risks of DevOps and System Administrators

In fact, one of the biggest risks is:

DevOps or system administrators on local machines because it is practical:

SSH keys
Deployment credentials
Cloud provider certificates
Kubernetes kubeconfig files
Admin tokens

It can store full authorized access information such as.

If a lifecycle script captures this information, the attacker can directly:

CI/CD management
Cloud account management
Production infrastructure
Registry access
Corporate management layer

is opened.

For this reason, precautions taken against supply-chain attacks should especially cover local environments of high-authorized users.

🛡 Modern Supply-Chain Security Approach

The following approach provides practical and sustainable protection against this type of attack.

1) Lifecycle Script Scan (install / postinstall analysis)

I’m using a small script that scans all packages in the dependency chain:

preinstall
install
postinstall
prepare

It automatically detects hooks such as It works with every change and before release.

Sample scanning script – `tools/check-scripts.js`

#!/usr/bin/env node
import { promises as fs } from 'node:fs';
import path from 'node:path';

const TARGET_SCRIPTS = new Set(['preinstall', 'install', 'postinstall', 'prepare']);
const root = path.resolve('node_modules');
const results = [];

async function fileExists(file) {
  try {
    await fs.access(file);
    return true;
  } catch {
    return false;
  }
}

async function inspectPackage(pkgDir) {
  const pkgPath = path.join(pkgDir, 'package.json');
  if (!(await fileExists(pkgPath))) return;

  const raw = await fs.readFile(pkgPath, 'utf8');
  const pkg = JSON.parse(raw);
  const scripts = pkg.scripts || {};
  const relevant = {};

  for (const key of TARGET_SCRIPTS) {
    if (scripts[key]) {
      relevant[key] = scripts[key];
    }
  }

  if (Object.keys(relevant).length > 0) {
    const suspicious = Object.values(relevant).some(cmd =>
      /curl|wget|node\s+-e|powershell|Invoke-WebRequest/i.test(cmd)
    );

    results.push({
      name: pkg.name,
      version: pkg.version,
      path: pkgDir,
      scripts: relevant,
      suspicious
    });
  }

  const nested = path.join(pkgDir, 'node_modules');
  if (await fileExists(nested)) {
    await walk(nested);
  }
}

async function walk(dir) {
  let entries;
  try {
    entries = await fs.readdir(dir, { withFileTypes: true });
  } catch {
    return;
  }

  for (const entry of entries) {
    if (!entry.isDirectory() || entry.name.startsWith('.')) continue;
    const full = path.join(dir, entry.name);
    if (entry.name.startsWith('@')) {
      await walk(full);
      continue;
    }
    await inspectPackage(full);
  }
}

async function main() {
  if (!(await fileExists(root))) {
    console.error('node_modules not found. Run npm ci first.');
    process.exit(1);
  }
  await walk(root);
  console.log(JSON.stringify(results, null, 2));
}

main();

2) Disabling Lifecycle Scripts in CI

Each build is run as follows:

npm ci --ignore-scripts

In this way, no lifecycle script runs automatically. Confirm manually if necessary:

npm rebuild

command can be used.

3) Automated Security Pipeline (Audit + Secret Scan + Lifecycle Analysis)

With every dependency update and every release:1. npm run scan:lifecycle

npm audit --production --audit-level=high
npx gitleaks detect --redact
Reports are written to the reports/security-check.log file
Prevents CI/CD release in critical situations

This mechanism provides constant control against supply-chain attacks.

4) Secure Development in DevContainer

When DevContainer first opens:

pnpm install --ignore-scripts
npm install --ignore-scripts
npm run scan:lifecycle

A rule like this is enforced. Automatic script execution is prevented in the local environment.

5) Deterministic Installation (lockfile discipline)

Always with package-lock.json commit
CI only works with npm ci
Version fluctuation is prevented

This approach closes the most common vector of supply-chain infections.

🎯 Result

Shai-Hulud and similar attacks are a critical warning for modern software suites: Not only the code we produce, but also the chain we use must be protected.

The approach described in this article:

Lifecycle script analysis scanning the dependency chain
Secure installation that prevents script execution in CI
Audit and secret scanning mechanisms
DevContainer security, including the local environment
Lockfile discipline

Thanks to this, it significantly reduces supply-chain risks.

Each team can add more advanced security policies according to their structure, but this is the basic architecture; It is a modern, practical and sustainable starting point.