What is a union based SQL injection attack?
Union Query SQL injection is a type of in-band injection attack that allows an attacker to extract information from the database quickly. This attack allows the attacker to combine more than one SQL commands into one SQL command. The response generated from the server is returned as HTTP response.
How does the union operator aid the attacker in performing SQL injection?
In SQL Injection, the UNION operator is commonly used to attach a malicious SQL query to the original query intended to be run by the web application. The result of the injected query will be joined with the result of the original query. This allows the attacker to obtain column values from other tables.
What is an example of what a SQL injection attempts to do?
Some common SQL injection examples include: Retrieving hidden data, where you can modify an SQL query to return additional results. Subverting application logic, where you can change a query to interfere with the application’s logic. UNION attacks, where you can retrieve data from different database tables.
Why is UNION based SQL injection used?
When an application is vulnerable to SQL injection and the results of the query are returned within the application’s responses, the UNION keyword can be used to retrieve data from other tables within the database. The individual queries must return the same number of columns. …
What is UNION based injection?
Union based SQL injection allows an attacker to extract information from the database by extending the results returned by the original query. The Union operator can only be used if the original/new queries have the same structure (number and data type of columns).
How does SQL injection attack work?
To perform an SQL injection attack, an attacker must locate a vulnerable input in a web application or webpage. When an application or webpage contains a SQL injection vulnerability, it uses user input in the form of an SQL query directly.
Why would you use UNION based SQL injection to exploit a database?
The reason for performing an SQL injection UNION attack is to be able to retrieve the results from an injected query. If the data type of a column is not compatible with string data, the injected query will cause a database error, such as: Conversion failed when converting the varchar value ‘a’ to data type int.
What are UNION based SQL?