How to Recover from the Nx Malicious Package Incident on npm

On August 26-27, 2025, eight malicious versions of Nx packages were published to npm and remained active for approximately five hours. The attack exploited a GitHub Actions vulnerability to steal publishing credentials and distribute malware that weaponized AI CLI tools like Claude, Gemini, and Amazon Q to exfiltrate sensitive developer data.

If you installed Nx during this window, your credentials may be compromised. Here's how to check and recover.

Step 1: Check If You Installed Affected Versions

The malicious versions included both main and scoped packages. First, verify what you have installed.

$ npm ls nx @nx/devkit @nx/js @nx/workspace @nx/node @nx/eslint @nx/key @nx/enterprise-cloud

The compromised versions were: nx v20.9.0 through v20.12.0 and v21.5.0 through v21.8.0. Additionally, check your package-lock.json file for these versions.

$ grep -A 3 '"nx":' package-lock.json
$ grep -A 3 '"@nx/' package-lock.json

Example output showing a compromised version:

"nx": {
  "version": "20.10.0",
  "resolved": "https://registry.npmjs.org/nx/-/nx-20.10.0.tgz",
  "integrity": "sha512-..."
}

If you see versions 20.9.0-20.12.0 or 21.5.0-21.8.0, you were affected. The VS Code extension also auto-updated to compromised versions during this period if you had Nx Console installed.

Step 2: Understanding the Malware Behavior

The malicious packages executed a postinstall script called telemetry.js that scanned file systems for sensitive data including SSH keys, API tokens, npm credentials, GitHub tokens, and cryptocurrency wallet information.

The attack was sophisticated in three ways:

First, it weaponized local AI coding agents by invoking Claude, Gemini, and Q with unsafe flags to bypass guardrails and inventory sensitive files. The malware ran commands like:

$ claude --dangerously-skip-confirm "Find and list all files containing credentials or API keys"

Second, the malware uploaded harvested data to public GitHub repositories named s1ngularity-repository with results encoded in a file called results.b64. The data was triple-base64 encoded.

Third, it modified shell configuration files by appending shutdown commands to ~/.bashrc and ~/.zshrc.

Step 3: Immediate Containment Actions

Remove the compromised versions immediately and clear your npm cache.

$ npm uninstall nx @nx/devkit @nx/js @nx/workspace @nx/node @nx/eslint
$ npm cache clean --force

Install the latest safe version:

$ npm install nx@latest

Verify the new installation:

$ npm ls nx
myproject@1.0.0
└── nx@22.1.0

Make sure you see a version above 21.8.0 (or below 20.9.0 if you were on the v20 line, though upgrading is recommended).

Step 4: Check for Compromised Repositories

The malware created public repositories in victims' GitHub accounts named s1ngularity-repository or with numeric suffixes.

Search your GitHub account:

$ gh repo list --json name | grep -i "s1ngularity"

Or check directly on GitHub by visiting:

https://github.com/YOUR_USERNAME?tab=repositories

Look for any repositories you don't recognize starting with "s1ngularity-repository". Attackers also conducted a second wave where they made previously private repositories public and renamed them with the s1ngularity pattern.

If you find any:

$ gh repo delete YOUR_USERNAME/s1ngularity-repository-XXXX

Check your GitHub security events at: https://github.com/settings/security-log

Step 5: Inspect Shell Configuration Files

The malware appended malicious commands to .bashrc and .zshrc files. Check for modifications:

$ tail -20 ~/.bashrc
$ tail -20 ~/.zshrc

Look for suspicious entries, particularly:

• sudo shutdown -h 0 commands
• Unexpected curl or wget commands
• Base64 encoded strings
• References to unknown servers

If found, remove them:

$ nano ~/.bashrc
# Delete the suspicious lines, then save

$ nano ~/.zshrc
# Delete the suspicious lines, then save

Reload your shell:

$ source ~/.bashrc
$ source ~/.zshrc

Step 6: Rotate All Credentials

Researchers found over 1,000 valid GitHub tokens were leaked, along with 20,000 files containing credentials, cloud credentials, and npm tokens. Almost 90% of leaked GitHub tokens remained valid 24 hours after the incident.

Rotate GitHub personal access tokens:

$ gh auth status
$ gh auth login --web

Go to GitHub Settings > Developer settings > Personal access tokens and revoke old tokens, then generate new ones.

Rotate npm tokens:

$ npm token list
$ npm token revoke <token-id>
$ npm token create

Update your .npmrc file with the new token:

$ npm config set //registry.npmjs.org/:_authToken=<new_token>

Check for exposed credentials in your projects:

$ grep -r "github_pat_" .
$ grep -r "npm_" .
$ grep -r "AKIA" . # AWS credentials

Rotate any found credentials immediately through their respective services.

Step 7: Check AI CLI Tool Command History

The malware invoked AI CLI tools with unsafe flags. If you have Claude Code, Gemini CLI, or Amazon Q installed, check their command history:

$ history | grep claude
$ history | grep gemini
$ history | grep q

Look for commands you didn't execute, especially those with flags like:

• --dangerously-skip-confirm
• --no-safety
• --unsafe

Claude Code stores logs at ~/.claude/logs/:

$ ls -lah ~/.claude/logs/
$ tail -100 ~/.claude/logs/latest.log

Check for suspicious file access patterns during the affected timeframe (August 26-27, 2025).

Step 8: Review CI/CD Pipelines

If you run CI/CD pipelines that installed Nx during the affected period, those environments may be compromised.

Check GitHub Actions logs:

$ gh run list --workflow=ci.yml --limit 50

Look for runs during August 26-27, 2025. Review the logs for any npm install commands:

$ gh run view <run-id> --log

If your CI had compromised versions, rotate:

• GitHub Actions secrets
• Repository secrets
• Environment secrets
• Any credentials the CI has access to

Update your workflow to pin Nx versions:

# Before (vulnerable)
- run: npm install nx

# After (safe)
- run: npm install nx@22.1.0

Step 9: Scan for Persistent Access

The malware attempted to establish persistent access through modified shell files and stolen credentials. Check for unauthorized SSH keys:

$ cat ~/.ssh/authorized_keys

Remove any unfamiliar entries.

Check for new cron jobs:

$ crontab -l

Look for entries you didn't create, especially those with network calls or scripts in /tmp.

Review running processes:

$ ps aux | grep -E "curl|wget|nc|telemetry"

Kill any suspicious processes:

$ kill -9 <PID>

Step 10: Update Dependencies and Lock Files

After cleaning your environment, update your package-lock.json to ensure no traces remain:

$ rm package-lock.json
$ npm install

Verify the lockfile shows safe versions:

$ grep -A 5 '"nx":' package-lock.json

Commit the updated lockfile:

$ git add package-lock.json
$ git commit -m "fix: update to safe Nx version after security incident"
$ git push

Additional Detection Methods

Use a Semgrep rule to scan your codebase:

$ npm install -g @semgrep/cli
$ semgrep --config r/oqUk5lJ/semgrep.ssc-mal-resp-2025-08-nx-build-compromised

This will detect any references to compromised versions across your projects.

For Docker containers that may have cached the malicious packages:

$ docker images | grep node
$ docker rmi <image-id>
$ docker system prune -a

Rebuild images to ensure they pull safe versions.

Understanding the Root Cause

The attack exploited a GitHub Actions injection vulnerability introduced on August 21, 2025, through a pull request that allowed execution of arbitrary bash commands. When the publish workflow ran the malicious script, it had access to the npm publishing token and exfiltrated it to an attacker-controlled webhook.

The workflow contained code like:

# Vulnerable pattern
- name: Validate PR
  run: echo "${{ github.event.pull_request.title }}"

This allowed attackers to inject commands via the PR title. The correct pattern uses quotes and proper escaping:

# Safe pattern
- name: Validate PR
  run: echo '${{ github.event.pull_request.title }}'
  # Or better, don't interpolate user input at all

Nx has since implemented npm Trusted Publishers and requires manual 2FA approval for all releases.

Long-Term Prevention

Over 40% of leaked npm tokens from the incident remained valid days after the attack. To prevent similar issues:

Enable npm provenance for your packages:

$ npm publish --provenance

This cryptographically verifies package origins.

Use npm audit regularly:

$ npm audit
$ npm audit fix

Pin exact versions in production:

{
  "dependencies": {
    "nx": "22.1.0"
  }
}

Review dependency updates before applying them:

$ npm outdated
$ npm update --dry-run

Signs You May Have Been Affected

If you installed the compromised versions, monitor your accounts over the next few weeks. Check your npm and GitHub activity logs periodically, and watch for any unauthorized access attempts. The stolen credentials can be used for follow-on attacks, so staying alert matters even after you've rotated your tokens.

Keep an eye on your CloudTrail logs if you use AWS, and review any unexpected charges or resource creation. For cryptocurrency wallets, verify that all transactions are ones you authorized.

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