An attacker launches an SQL injection attack on a web application by trying to force the application requesting the back-end database to perform multiple SELECT queries. Which technique exploits the SQL injection vulnerability on the web application?

Explanation & Hint:

There are essentially five techniques that can be used to exploit SQL injection vulnerabilities:

• Union operator – Typically used when an SQL injection vulnerability allows a SELECT statement to combine two queries into a single result or a set of results.
• Boolean – Used to verify whether certain conditions are true or false.
• Error-based – Used to force the database to generate an error to enhance and refine an attack (injection).
• Out-of-band – Used to obtain records from the database by using a different channel.
• Time delay – It is possible to use database commands to delay answers.