SQL injection (SOU) attacks attempt to inject SOL syntax into web requests, which may Bypass authentication and allow attackers to access and/or modify data attached to a web application. Which of the

Union-based SQLI appends a UNION SELECT statement to the original query, causing the database to return combined result sets that include attacker-chosen data from any accessible table. This technique can be extended to leverage database-server-side request features - including DNS lookups via functions such as load_file() combined with UNC paths or UTL_HTTP in Oracle - to route extracted data to an attacker-controlled external server.

Out-of-band SQLI is a distinct technique that relies entirely on the database server initiating a separate DNS or HTTP channel to exfiltrate data, rather than using the UNION operator to retrieve data within the original response.

In-band SQLI is the broader category encompassing both error-based and union-based subtypes, referring to any injection where data is returned through the same HTTP channel as the attack - it is not a standalone technique that leverages DNS requests.

Time-based blind SQLI infers database truth conditions by measuring deliberate response delays introduced with functions like SLEEP() or WAITFOR DELAY, and does not extract or transmit data through DNS requests.