Trusting Third Party Code: A Practical Guide

TL;DR

Using code or services from others always carries risk. This guide shows how to check what you’re using, keep it secure, and limit the damage if things go wrong.

1. Understand What You’re Using

1. Know the Source: Where did this code/service come from? A well-known company is generally better than a random website.
2. Licensing: Check the license (e.g., MIT, Apache 2.0, GPL). Understand what you’re allowed to do with it. Some licenses require you to share your changes.
3. Dependencies: What other code does this rely on? A long list of dependencies increases risk – each one is a potential weak point. Tools like dependency checkers (see section 6) can help.
4. Purpose: Exactly what does it do? Don’t use code you don’t understand, or that performs functions beyond your needs.

2. Security Checks Before Using

1. Code Reviews: If possible, have someone else look at the code before you integrate it. Fresh eyes can spot problems you missed.
2. Static Analysis: Use tools to automatically scan the code for potential vulnerabilities (e.g., SonarQube, linters). These won’t find everything but are a good start.
3. Vulnerability Databases: Check if known security issues exist for this code or its dependencies. NVD (National Vulnerability Database) is a good resource.
4. Reputation: Search online for reports of security problems with the code or service.

3. Secure Integration

1. Principle of Least Privilege: Give the code/service only the permissions it absolutely needs to function. Don’t grant broad access.
2. Input Validation: Always validate any data you send to the third-party code or service. This prevents attacks like SQL injection and cross-site scripting (XSS).
3. Output Encoding: If the code/service returns data, encode it properly before displaying it on your website or using it in other systems.
4. Sandboxing: Where possible, run the code in a sandboxed environment to limit its access to your system (e.g., containers like Docker).

4. Ongoing Monitoring

1. Regular Updates: Keep the code/service updated to the latest version. Updates often include security fixes. Automate this process if possible.
2. Log Everything: Log all interactions with the third-party code/service. This helps you detect and investigate suspicious activity.
3. Error Handling: Implement robust error handling to catch unexpected errors that could indicate a problem.
4. Performance Monitoring: Unusual performance changes can sometimes signal a security issue.

5. Incident Response Plan

1. Have a Plan: What will you do if the code/service is compromised? Document your response steps.
2. Isolation: Be able to quickly isolate the affected systems to prevent further damage.
3. Communication: Know who needs to be notified (e.g., security team, legal counsel).
4. Recovery: Have a plan for restoring your systems and data.

6. Useful Tools

• Dependency Checkers: OWASP Dependency-Check (Java) and Snyk (multiple languages) scan your project’s dependencies for known vulnerabilities. Example using Snyk CLI:

  snyk test

• Static Analysis Tools: SonarQube (multiple languages) and linters for your specific programming language.
• Web Application Firewalls (WAFs): Protect against common web attacks, including those targeting third-party code.