-6506' - Union All Select 34,34,34,34,34,34,34,34,34#

: Only allow expected characters (e.g., alphanumeric).

The string is designed to trick a database into merging its legitimate results with "fake" data injected by an attacker. -6506' UNION ALL SELECT 34,34,34,34,34,34,34,34,34#

This string is a classic example of a payload. Specifically, it uses a UNION ALL SELECT technique to extract data from a database by appending a second query to the original one. 🛡️ Understanding the Payload : Only allow expected characters (e

: A comment character in MySQL that "turns off" the rest of the original, legitimate code to prevent syntax errors. 🛠️ How to Prevent SQL Injection : Only allow expected characters (e.g.

: Closes the original query's string literal and uses a value ( -6506 ) that likely returns no results, making the injected data easier to see.