Secure Coding Languages: A Practical Guide

TL;DR

No programming language is inherently ‘secure’. Security depends on how you write code, not which language you use. Some languages make it easier to avoid common pitfalls than others. This guide explains why and what steps you can take.

Understanding the Problem

The idea of a ‘secure’ language is misleading. All languages have potential vulnerabilities. A poorly written program in Python can be just as insecure as one in C. Security issues usually come from:

• Human error: Mistakes made by developers (buffer overflows, SQL injection, cross-site scripting).
• Design flaws: Poorly thought-out application architecture.
• External libraries: Vulnerabilities in code you didn’t write yourself.

However, some languages offer features that help reduce these risks.

Step 1: Languages with Built-in Safety Features

Certain languages are designed to be safer by default:

• Rust: Focuses on memory safety and preventing data races. It’s excellent for systems programming where low-level control is needed, but requires a steeper learning curve.

  // Example of Rust's ownership system preventing dangling pointers

• Go: Includes built-in concurrency features that help avoid common race conditions. It also has strong typing and garbage collection.

  // Go example showing goroutines for safe concurrent operations

• Java/C#: Managed languages with automatic memory management (garbage collection) which reduces the risk of buffer overflows and memory leaks. They have robust type systems and security features built-in, but can still be vulnerable to other attacks.

  // Java example using secure random number generation

Step 2: Languages Prone to Common Issues

Some languages are historically more associated with vulnerabilities due to their features (or lack thereof):

• C/C++: Powerful but require manual memory management, making them susceptible to buffer overflows, dangling pointers, and other memory-related errors.
• PHP: Historically had security issues, though modern versions have improved significantly. Still requires careful coding practices to avoid SQL injection and cross-site scripting (XSS).

  // PHP example of prepared statements to prevent SQL Injection

Step 3: Secure Coding Practices – The Most Important Step

Regardless of the language, these practices are crucial:

1. Input Validation: Always validate user input. Never trust data from external sources.
   • Sanitise inputs to remove potentially harmful characters.
   • Use whitelisting (allow only known good values) instead of blacklisting (block known bad values).
2. Output Encoding: Encode output properly to prevent XSS attacks.
3. Authentication and Authorisation: Implement strong authentication and authorisation mechanisms. Use established libraries where possible.
4. Regular Security Audits: Regularly review your code for vulnerabilities, ideally with automated tools (static analysis).
5. Keep Libraries Updated: Update third-party libraries to the latest versions to patch known security flaws.
6. Least Privilege Principle: Run applications with the minimum necessary permissions.

Step 4: Static and Dynamic Analysis Tools

These tools help identify vulnerabilities automatically:

• Static Analysis: Examines code without running it (e.g., SonarQube, Coverity). Useful for finding potential bugs early in the development process.
• Dynamic Analysis: Tests code while it’s running (e.g., fuzzing, penetration testing). Helps identify runtime vulnerabilities.

Step 5: Cyber security Awareness and Training

Educate developers about common cyber security threats and secure coding practices. Regular training is essential to keep skills up-to-date.