-1' OR 5*5=25 or '8g9pTWkb'='

This looks like a partial SQL injection payload rather than a valid query. It’s the kind of string an attacker might try to inject into a vulnerable query to alter the logic of a WHERE clause.

Key idea explained (high level, defensive focus):

• 5*5=25 is always true. In SQL, that boolean expression evaluates to true.
• An injected OR clause such as ... OR 5*5=25 ... can cause the WHERE clause to be true for all rows, potentially bypassing authentication or other checks if the input is concatenated into a SQL string without proper parameterization.
• The parts with quotes (like -1' and '8g9pTWkb'=) are attempts to break out of a string literal and add additional conditions. The final result depends on how the input is inserted into the SQL query and the database engine’s operator precedence.

Important caveat:

• As written, the snippet is incomplete (the final =' is not a complete comparison), and on its own it won’t run. In a real vulnerable query, parts like OR 5*5=25 can still make the condition true, which is the point of the attack in many examples.

Defensive recommendations (exam-ready):

• Use parameterized queries/prepared statements for all user inputs. Do not concatenate user input into SQL strings.
  • Example (concept): SELECT * FROM users WHERE username = ? AND password = ?
• Validate and sanitize inputs, but rely on parameterization for security, not manual escaping.
• Apply least-privilege database accounts (the app should not connect with an account that can do more than necessary).
• Use an ORM or query builder that handles parameterization automatically.
• Enable proper error handling to avoid leaking database error details to users.
• Consider a Web Application Firewall (WAF) and perform regular security testing (in a controlled lab) to detect injection patterns.
• If you’re teaching or studying this for an exam, be able to recognize:
  • Tautologies that can make WHERE clauses always true (e.g., 1=1, 5*5=25).
  • How closing quotes or comment syntax (e.g., --) are used in some payloads.
  • Why parameterization prevents these payloads from altering query logic.

If you want, I can turn this into a quick exam-style question (e.g., showing vulnerable code and asking for fixes) or provide a safe lab example demonstrating both vulnerable and secure approaches. Would you like that?