-1' OR 5*5=26 or 'Ypbr21jD'='

That looks like an SQL injection payload. I can’t help with exploiting systems, but I can explain what it is and how to defend against it—useful for exams and safe practice.

What this kind of string attempts to do (high level)

• It tries to break out of a string literal that came from user input in an SQL query.
• It then injects extra SQL (often using OR and boolean expressions) to alter the logic of the WHERE clause.
• The goal is to bypass authentication or retrieve data without the intended password check.

Why this is dangerous

• If you concatenate user input directly into SQL queries, attackers can manipulate the query structure.
• It can lead to login bypass, data leakage, data corruption, or even full compromise depending on the DB and privileges.

Defensive measures (best practices)

• Use parameterized queries (prepared statements) for all user inputs.
• Do not build SQL by string concatenation; pass values as bind parameters.
• Use a strong ORM or DB API that enforces parameterization.
• Validate inputs with allowlists (e.g., restrict username/password formats) but do not rely on validation alone.
• Use least-privilege database accounts (the app should not own superuser rights).
• Disable detailed database error messages in production to avoid leaking schema details.
• Consider additional protections like input length limits and WAF rules for obvious injection patterns.
• Regularly test with safe, permissioned security testing in a dedicated environment.

Concrete examples (safe coding practices)

• Python (psycopg2 or similar): cur.execute("SELECT * FROM users WHERE username = %s AND password = %s", (username, password))

• JavaScript (Node.js with mysql2 or pg): connection.execute("SELECT * FROM users WHERE username = ? AND password = ?", [username, password])

• PHP (PDO): $stmt = $pdo->prepare("SELECT * FROM users WHERE username = :username AND password = :password"); $stmt->execute(['username' => $username, 'password' => $password]);

Exam-focused takeaway

• Insecure pattern: building SQL with string concatenation and injecting user input.
• Secure pattern: always use parameterized queries and separate code from data.
• Common attack signature includes input that ends a string literal (a quote) and followed by OR conditions or tautologies; recognize these as red flags for SQL injection.

If you want, tell me your preferred language or the exact exam scenario, and I can tailor more concrete examples or practice questions.