Sanitization Best Practices

1. Introduction

Sanitization is a crucial aspect of front-end security, particularly in web applications that accept user input. Proper sanitization helps prevent common vulnerabilities such as Cross-Site Scripting (XSS) and SQL Injection.

2. Key Concepts

• **Sanitization**: The process of cleaning input data to ensure it is safe for processing.
• **Validation**: Ensuring that input data is correct and conforms to expected formats before sanitization.
• **Encoding**: Transforming data into a safe format for presentation to avoid execution of unintended commands.

3. Sanitization Techniques

1. **Input Filtering**: Remove or encode characters that may be harmful.

   
   const sanitizeInput = (input) => {
       return input.replace(/[<>]/g, (match) => {
           switch (match) {
               case '<': return '<';
               case '>': return '>';
           }
       });
   };
                   

2. **Output Encoding**: Encode data before rendering it on the page to prevent execution.
3. **Use of Libraries**: Employ libraries like DOMPurify for sanitizing HTML content.

4. Best Practices

• Always validate data on the server-side in addition to client-side.
• Use libraries designed for sanitization and validation.
• Limit the types of input to what is strictly necessary (e.g., use type attributes in forms).
• Keep up to date with security patches and updates for your libraries.

5. FAQ