[질문] -1' OR 2+16-16-1=0+0+0+1 or 'GMkH9Fpr'='

I can’t help create or refine SQL injection attacks or other exploits. If your goal is security testing, remember to only test systems you own or have explicit permission to test.

I can, however, explain at a high level what that kind of string is trying to do and — importantly — how to prevent and fix SQL injection vulnerabilities.

High-level intent (conceptual)

• Payloads like that attempt to break out of a quoted value and inject additional SQL logic so the condition becomes true (for example to bypass authentication or change a query’s behavior).
• The general attack pattern is: close or escape a string literal, add an always-true expression or other SQL, and optionally terminate the statement or comment out the remainder of the original query.

Defensive measures (what actually fixes it)

1. Use parameterized queries / prepared statements

   • Never construct SQL by concatenating untrusted input into SQL strings.
   • Use proper parameter binding so the DB treats user input as data, not SQL.

2. Use an ORM or parameterized APIs

   • ORMs (Django ORM, SQLAlchemy, Hibernate, Entity Framework) and DB APIs provide safe parameter binding if used correctly.

3. Principle of least privilege

   • Database accounts used by the application should have only the permissions they need (no admin/root privileges).

4. Input validation and output encoding

   • Validate input format and length (but validation is not a substitute for parameterized queries).
   • Encode output when rendering to different contexts (HTML, JS, etc.).

5. Avoid dynamic SQL

   • Avoid building SQL that needs user input to inject table/column names. If you must, whitelist allowed names and map them to safe values.

6. Use a Web Application Firewall (WAF) and logging

   • WAFs can provide an additional layer of protection and block common payloads.
   • Log, monitor, and alert on suspicious queries and failed attempts.

7. Secure configuration and patching

   • Keep DB and application libraries patched.
   • Disable error messages that reveal SQL or schema details to users.

Secure coding examples (parameterized queries)

• PHP (PDO)

  • Use prepared statements and bound parameters (do not interpolate user input into the SQL string).

• Python (psycopg2)

  • Use cursor.execute("SELECT ... WHERE id = %s", (user_id,))

• Node.js (mysql2 / pg)

  • Use parameter placeholders and pass parameters separately (pool.query(sql, params))

(If you’d like, tell me which language and database you’re using and I’ll show a secure example for that stack.)

Testing and responsible disclosure

• If you want to test an application, use authorized tools and get written permission.
• Use security scanners (OWASP ZAP, Burp Suite) responsibly and follow disclosure policies.

If your intention is defensive, paste (or describe) the specific code that’s handling DB queries in an application you own and I’ll show exactly how to fix it so it’s safe from SQL injection.