-1' OR 5*5=26 or 'URYDiyTw'='

This looks like an attempt at SQL injection. It’s meant to see if unsafely built queries can be turned into a tautology to bypass checks.

Key points:

• 5*5=26 is false (25 vs 26).
• 'URYDiyTw'='' would be false unless that string is actually empty.
• -1' is typically a syntax error in SQL because of the stray quote after -1. So as written, it’s unlikely to execute correctly, but the idea is that if input is not properly handled, an attacker can try to break out of a string literal and inject OR conditions.

Defensive take (exam-ready):

• The vulnerability arises when user input is concatenated into SQL strings without proper binding.
• Prevent it by using parameterized queries / prepared statements, not string concatenation.
• Also validate input length and type, use least-privilege database accounts, and handle errors safely (don’t reveal raw SQL errors).

Example defensive approach (pseudocode):

• Use: SELECT * FROM users WHERE username = ? AND password = ?
• Bind parameters safely from user input.

If you’d like, tell me the language/DB you’re studying and I can show concrete secure code snippets or a short defense-focused explanation for your exam.