The snippet uses a UNION ALL SELECT statement, which is a classic technique used to: in a database table.
If this code is entered into a search bar, login field, or URL and successfully executes, it means an attacker could potentially download your entire user database, including passwords and personal information. How to protect your website The snippet uses a UNION ALL SELECT statement,
by printing a specific "canary" string (in this case, the long string starting with qbqvq... ) to the screen. If that string appears on the webpage, the attacker knows the site is exploitable. Why this is a security risk or URL and successfully executes