SQL Injection

SQL Injection (SQLi) is a critical web security vulnerability that allows an attacker to interfere with the queries that an application makes to its database. This attack occurs when malicious SQL code is inserted into a user input field, which is then executed by the backend database because the application failed to properly sanitize or parameterize the input. By successfully exploiting this flaw, an attacker can bypass authentication, view, modify, or delete data, and potentially gain administrative control over the entire database, making it one of the most dangerous threats to data-driven applications.

1. Introduction to SQL Injection
   1. Definition and Core Concepts
      1. What is SQL Injection
      2. Injection Attack Fundamentals
      3. SQL Injection vs Other Injection Types
   2. The Underlying Vulnerability
      1. Unsanitized User Input
      2. Trust Boundaries in Applications
      3. Dynamic Query Construction
      4. Code-Data Separation Failure
   3. Common Input Sources
      1. URL Parameters
      2. Form Fields
      3. HTTP Headers
      4. Cookies
      5. Hidden Form Fields
      6. AJAX Requests
   4. Attack Impact Categories
      1. Data Confidentiality Breaches
         1. Unauthorized Data Access
         2. Sensitive Information Disclosure
         3. Customer Data Exposure
      2. Data Integrity Compromise
         1. Unauthorized Data Modification
         2. Data Corruption
         3. Record Deletion
      3. Authentication Bypass
         1. Login Mechanism Circumvention
         2. Privilege Escalation
         3. Administrative Access
      4. Availability Disruption
         1. Denial of Service
         2. Resource Exhaustion
         3. Application Crashes
      5. System Compromise
         1. Command Execution
         2. File System Access
         3. Network Lateral Movement
   5. SQL in Web Applications
      1. Role of SQL in Dynamic Applications
      2. Application Architecture Patterns
      3. Database Connectivity Models
      4. Query Construction Methods