Course 1 - BurpSuite Bug Bounty Web Hacking from Scratch | Episode 9: Understanding and Finding SQL Injection Vulnerabilities

In this lesson, you’ll learn about:SQL Injection (SQLi) — definition & importance: what SQL is (Structured Query Language) and why data-driven apps are high-value targets for injection attacks.Core mechanism: how attackers inject malicious input into dynamic SQL statements (queries built from runtime parameters) to alter logic — e.g., commenting out parts of a query or appending always-true conditions.Types of SQLi: error-based, blind (boolean), time-based, and union-based injections — each exploits the DB engine differently and requires different discovery/exploitation techniques.Potential impact: full database disclosure (dumping data), modifying/inserting/deleting records, or otherwise corrupting application data and functionality — impact depends on DB engine and privileges.Discovery approach — fuzzing & logic-first mindset: understand the application flow and likely backend queries, then feed “weird input” to break or alter the SQL (fuzzing is the primary discovery method).Basic test techniques:Quotes: submit single (') or double (") quotes to provoke syntax errors — a common initial test for SQLi.Backslashes / escapes: use \ (or DB-specific escape chars) to break query parsing in some engines (e.g., MySQL).Choose the technique that matches the app’s input handling (single-quote, double-quote, or backslash may work differently).Automation: use tools (or Burp Intruder) to automate payload lists once you know which delimiter/escape style affects the target. Monitor responses for errors, content changes, or timing differences.Detection signals: SQL errors in responses, changes in content length/body, boolean differences, or time delays (for time-based tests) indicate possible vulnerability.Next steps after detection: escalate from proof-of-concept errors to controlled data extraction techniques (union queries, blind extraction techniques, or time-based exfiltration) while keeping tests minimal and authorized.Analogy (teaching aid): like a locksmith trying different picks (quotes, backslashes) in a lock (input field) to find the one that opens the mechanism (causes the backend SQL to fail or execute attacker-controlled logic).Ethics & safety note: always test within authorized scope, avoid destructive payloads, and document findings/steps for reproducible PoCs.You can listen and download our episodes for free on more than 10 different platforms:https://linktr.ee/cybercode_academy