-1' OR 560=560 or 'NyqYC96j'='

What you pasted looks like a SQL injection payload. In simple terms:

• It tries to break out of the normal input context in a SQL query and add an OR condition that is always true (a tautology).
• If the application builds SQL by concatenating strings with user input, this can cause the WHERE clause to always evaluate to true, potentially bypassing authentication or exposing data.

Key idea in high level terms:

• The attacker closes the current string literal, injects something like OR 1=1 (a tautology), and hopes the rest of the query still makes sense to the database.
• If the app doesn’t sanitize input or use parameterized queries, the injected logic can run with the rest of the query.

Defensive practices (how to prevent this in exams or real apps):

• Use parameterized queries/prepared statements everywhere. Do not build SQL by concatenating user input.
  • Example (conceptual, not language-specific): SELECT * FROM users WHERE username = ? AND password = ?
  • Then bind user input to the parameters.
• Validate and sanitize input:
  • For numeric fields, reject anything that isn’t a number.
  • Use allowlists for expected formats (e.g., email patterns, usernames).
• Use least-privilege database accounts:
  • The application should connect with an account that has only the necessary rights (e.g., read/write restricted to what’s needed).
• Disable or restrict multi-statement execution if your DB supports it.
• Prefer stored procedures with parameters, not string-built SQL.
• Use proper password storage:
  • Never store or compare plain passwords; store salted hashes (bcrypt, Argon2, etc.) and compare the hash.
• Add web/app security controls:
  • Web Application Firewall (WAF) rules, input validation at the boundary, and regular security testing in a controlled environment.

If you want, I can:

• Give a brief exam-ready summary sentence.
• Show a safe, minimal code example in your preferred language (e.g., Python, Java, C#) illustrating parameterized queries.
• Outline typical exam questions about SQL injection and defensive measures.