How to enable input validation and filtering mechanisms immediately when a SQL injection attack occurs?

To enable input validation and filtering mechanisms immediately when a SQL injection attack occurs, you need to implement a combination of proactive and reactive measures. Here's how:

1. Input Validation

• Whitelist Validation: Accept only expected input patterns (e.g., numbers, alphanumeric strings) and reject anything else.
  Example: If a field expects an email, validate it against a regex like ^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$.
• Type and Length Checks: Ensure inputs match expected data types and lengths.

2. Parameterized Queries (Prepared Statements)

• Use parameterized queries instead of dynamic SQL to separate code from data.
  Example (in Python with SQLite):

  cursor.execute("SELECT * FROM users WHERE username = ? AND password = ?", (username, password))
  

3. Web Application Firewall (WAF)

• Deploy a WAF to detect and block SQL injection patterns in real-time.
  Example: Tencent Cloud's Web Application Firewall (WAF) can identify malicious SQL payloads and block requests before they reach your application.

4. Error Handling

• Avoid exposing database errors to users, as they may reveal sensitive information. Log errors securely instead.

5. Real-Time Monitoring & Blocking

• Use intrusion detection systems (IDS) or runtime application self-protection (RASP) to block attacks dynamically.
  Example: Tencent Cloud's Host Security service monitors for suspicious SQL queries and can automatically block malicious traffic.

6. Regular Security Testing

• Conduct penetration testing and code reviews to identify vulnerabilities before attackers exploit them.

By combining these measures, you can effectively mitigate SQL injection attacks as they occur. For cloud-based solutions, Tencent Cloud provides robust tools like WAF and Host Security to enhance protection.