: An attacker starts with one NULL and keeps adding more (e.g., NULL, NULL , then NULL, NULL, NULL ).
: If the number of NULL values does not match the original query's column count, the server usually returns an error (like a 500 Internal Server Error). : An attacker starts with one NULL and keeps adding more (e
: Attackers use NULL because it is compatible with almost every data type (integers, strings, dates), making it the "safest" way to avoid syntax errors while testing column counts. : This represents the original input (like a
: This represents the original input (like a product category or search term) that the application expects. SQL injection UNION attacks | Web Security Academy
: When the number of NULL s matches exactly (in your case, 8 columns), the page will load normally or show an extra blank row, confirming the database structure. Why This Matters
Once an attacker knows there are 8 columns, they can replace the NULL values with commands to extract sensitive data, such as usernames, passwords, or database versions. SQL injection UNION attacks | Web Security Academy
: This command attempts to append a new set of results to the original query's output.