-1" OR 5*5=26 --

It looks like a classic SQL injection payload. Here’s a quick, exam-friendly breakdown and safe defense notes.

What the string is doing (high level)

• -1" attempts to terminate a string literal in a SQL query.
• OR introduces an extra condition to be evaluated by the WHERE clause.
• 5*5=26 is a boolean expression (it’s false, since 25 ≠ 26).
• -- starts a SQL comment, so the rest of the original query after that point is ignored.
• Together, this is a means to try to alter the logic of a query (often to bypass authentication) while discarding the remainder of the original query.

Why this matters

• It exploits dynamic SQL construction where user input is concatenated into a SQL statement.
• If the application doesn’t properly sanitize or parameterize input, attackers can manipulate the query structure.

Exam prep: key concepts to know

• SQL injection vulnerability: when user input is treated as code inside a SQL query rather than as data.
• Common goals: bypass login, retrieve data, or modify data.
• Defensive patterns:
  • Use prepared statements/parameterized queries (never concatenate user input into SQL).
  • Validate input with a whitelist for fields that have limited formats.
  • Use least-privilege database accounts (the app should not own full admin rights).
  • Disable detailed database errors being shown to users; log them securely.
  • Consider using ORM/query builders that handle escaping automatically.
  • Regularly test with safe, controlled lab data to verify defenses.

Safe example (showing vulnerability vs. defense)

• Vulnerable pattern (for understanding the risk):
  • query = "SELECT * FROM users WHERE username = '" + user_input + "' AND password = '" + pass_input + "'"
  • This is vulnerable because user_input and pass_input are injected into the SQL text.
• Secure pattern (recommended):
  • Use parameterized queries
  • Example in pseudocode:
    • query = "SELECT * FROM users WHERE username = ? AND password = ?"
    • execute(query, [user_input, pass_input])
  • The database treats the inputs as data, not SQL code.

If you want, tell me your preferred language or framework (Python, Java, PHP, etc.), and I can show concrete, ready-to-use, secure code snippets and a quick quiz-style practice question relevant to your exam. And as always with this topic, use such knowledge only in legal, ethical, and controlled learning environments.