Question

Provide at least 4 examples of different types of SQL injection that can occur and the impact that    each might have. Brief expalnation

Answer 1

1. Unsanitized Input

Unsanitized input is a common type of SQLi attack in which the attacker provides user input that isn’t properly sanitized for characters that should be escaped, and/or the input isn’t validated to be the type that is correct/expected.

For example, a website used to pay bills online might request the user’s account number in a web form and building a SQL query string dynamically with the account number the user provided, it might look something like this:

“SELECT * FROM customers WHERE account = ‘“ + userProvidedAccountNumber +”’;”

It leaves the door open for attackers. If someone decided to provide an account number of “‘ or ‘1’ = ‘1”, that would result in a query string of:

“SELECT * FROM customers WHERE account = ‘’ or ‘1’ = ‘1’;”

Due to the ‘1’ = ‘1’ always evaluating to TRUE, sending this statement to the database will result in the data for all customers being returned instead of just a single customer.

Impact :

• Authentication Bypass, Information Disclosure, Data Loss, Data theft, and Data Integrity loss.
• Denial of service and at times System Compromise.

2. Blind SQL Injection

Also referred to as Inferential SQL Injection, a Blind SQL injection attack doesn’t reveal data directly from the database being targeted. Rather, the attacker closely examines indirect clues in behavior. Details within HTTP responses, blank web pages for certain user input, and how long it takes the database to respond to certain user input are all things that can be clues depending on the goal of the attacker. They could also point to another SQLi attack avenue for the attacker to try.

Impact:

• Subverting Applications Logic ( In simple words you try to understand the application logic and hence try to manipulate it)
• The results of a query you control are not returned in the application's responses.

3. Out-of-Band Injection

This attack is bit more complex and may be used by an attacker when they cannot achieve their goal in a single, direct query-response attack. Typically, an attacker will craft SQL statements that, when presented to the database, will trigger the database system to create a connection to an external server the attacker controls. In this fashion, the attacker can harvest data or potentially control behavior of the database.

Impact :

• Reading, updating and deleting arbitrary data or tables from the database
• Executing commands on the underlying operating system

4. Second Order Injection

A Second Order Injection is a type of Out-of-Band Injection attack. In this case, the attacker will provide an SQL injection that will get stored and executed by a separate behavior of the database system. When the secondary system behavior occurs (it could be something like a time-based job or something triggered by other typical admin or user use of the database) and the attacker’s SQL injection is executed, that’s when the “reach out” to a system the attacker controls happens.

Impact :

• The potential to target administrators of the application and the supporting environment.
• The potential to affect an organisation's internal hosts (e.g. help-desk workstations and databases)
• The ability to "seed" the application data storage areas with attack code prior to exploitation.