The string provided is a specific type of payload used by automated security scanners or malicious actors to test for and exploit database vulnerabilities. Technical Breakdown

: These act as placeholders to match the exact number of columns expected by the original query.

Ensure your application uses parameterized queries or prepared statements to prevent these characters from being executed as commands. You should also check your logs for any successful responses containing the string LBzNMMwdaChxayPTeQETdoUpXSqDSedwqCWKLDNE , which would indicate a successful breach.

: A comment marker that tells the database to ignore the rest of the original query, preventing syntax errors.

: Likely used as an invalid ID to force the original query to return no results, making the injected data the only output.

This payload is designed to perform a , which attempts to combine the results of the original query with a new, attacker-controlled query.

If this string was found in your server logs or application inputs, it indicates that an was performed against your system. It is a signature of a tool checking if it can "reflect" data back to itself through your database.

Are you seeing this in your or during a security audit ?