: This is likely a random "cache-buster" or unique identifier used by automated security scanners (like Burp Suite or Acunetix) to track which specific payload triggered a response. Why you are seeing this

The string you provided, '{KEYWORD}' UNION ALL SELECT NULL,NULL,NULL,NULL,NULL-- bWmV , is a classic example of a used for database exploitation and security testing. What this string does

: This is a SQL comment. It tells the database to ignore everything that follows it, effectively neutralizing the rest of the original, legitimate code.

: This ensures the database treats input as data only, never as executable code.

If you found this in your website logs, comment sections, or form submissions, it means an or a person is testing your site for security flaws. They are looking to see if your application is "injectable," which could allow them to steal data or bypass login screens. How to stay safe To prevent these types of attacks, developers should:

: This is the core of the attack. It tells the database to append the results of a second query to the results of the first one.

: Always filter and validate data coming from users.

: A WAF can automatically block requests containing common injection patterns like UNION SELECT .