It looks like a SQL‑injection style payload. Briefly:
- The expression: "-1" OR 2+989-989-1 = 0+0+0+1 --
- Arithmetic: 2+989-989-1 = 1 and 0+0+0+1 = 1, so the comparison is 1 = 1 (true).
- The OR true makes the whole WHERE condition true, and the trailing -- begins a SQL comment that ignores the rest of the query.
- Intent: force the WHERE clause to always be true so the query returns data (classic authentication bypass / data-exfiltration technique).
If your goal is defense, here are practical recommendations (don’t run this against systems you don’t own or have permission to test):
Use parameterized queries / prepared statements (do not build SQL by concatenating user input).
- Python (psycopg2):
cursor.execute("SELECT * FROM users WHERE username = %s AND password = %s", (user, pwd))
- PHP (PDO):
$stmt = $pdo->prepare('SELECT * FROM users WHERE username = ? AND password = ?');
$stmt->execute([$user, $pwd]);
- Node (mysql2):
connection.execute('SELECT * FROM users WHERE id = ?', [id]);
Validate and constrain input:
- For numeric fields, cast/validate to integers.
- Enforce length and allowed character sets for text fields.
- Reject obviously malicious payloads in input validation (as an additional layer, not a primary defense).
Least privilege and safe error handling:
- DB accounts should have only necessary privileges.
- Don’t display raw DB errors to users.
Use ORM or stored procedures where appropriate (still use parameterized APIs).
Additional controls:
- Web application firewall (WAF) to block common injection patterns.
- Logging and alerting for suspicious queries.
- Regular penetration testing in an authorized environment and secure code review.
If you’d like, tell me what language/framework and query you’re using and I can show a secure version of that specific query.