What is an SQL Injection?

An SQL injection in programming is a hacking technique that exploits web applications that use client-supplied data in SQL queries. Even though it’s quite simple to protect against, there is an alarming amount of commercial systems connected to the Internet that are vulnerable to SQL injections.

SQL Injection Concerns

According to Microsoft, SQL injection attacks pose a serious security threat to the security of Web applications, because they allow cyber-attackers to obtain unrestricted access to databases, associated applications and the sensitive information contained within them. Hackers who gain access to their consumer, industry or business databases can steal identities, commit crimes and engage in fraud. In the most extreme cases, attackers use an SQL injection vulnerability to take control of the system that hosts the Web application. As a result, they can corrupt the system and steal massive amounts of confidential data. Most of the data breach horror stories in the news refer to SQL injection cyber-crimes.

Although security experts and researchers have proposed various methods to mitigate the SQL injection threat, most approaches fail to address the full scope of the problem or they have notable limitations. Because most security practitioners are only familiar with certain hacking techniques and SQL injection vulnerabilities, most solutions are not comprehensive. In order to be successful, IT security professionals must be familiar with the different types of SQL injection attacks and know individual detection and prevention techniques.

SQL Injection Vulnerabilities

An SQL injection refers to a type of code-injection attacks where user provided data is included in an SQL query, so the user’s input is treated like an SQL code. By taking advantage of these vulnerabilities, a hacker can submit SQL commands directly to the target database. These attacks are aimed at any Web application that receives input from external users and incorporates it into internal queries within a database. Almost all Web applications available on the Internet or within corporate systems are vulnerable to SQL injection attacks.

The cause of SQL injection vulnerabilities lies in the insufficient validation of user input. To mitigate these problems, Web developers use coding guidelines that promote defensive coding practices. For example, a simple solution is to require encoding user input validation. A systematic application of these techniques is an effective solution, but fixing large amounts of code-bases that may contain SQL injection vulnerabilities is a labor-intensive task. Each attack type must be documented with its individual characterization, negative side effects and proposed solution.

Comprehensive Testing

Comprehensive testing is the best way to fully protect vulnerable databases and Web applications. Thoroughly checking a web application for SQL injection vulnerability takes multiple documented tests. Every parameter of all server scripts should always be consistently checked. Development teams are notoriously inconsistent, because the programmer who designed the primary script may have had nothing to do with the development of secondary script.

For example, one parameter in a server script might be designed by a skilled developer without any vulnerabilities, but another programmer who edits the server script may lack sufficient training and knowledge. Web development, server scripting and application coding must be based on a single, unified set of standards and protocols. The best testing procedure is to simply examine each parameter individually.

Related Resource: Firewall

An SQL injection in programming results in vulnerabilities that can be used to create some of the most serious operational, financial and confidentiality threats for organizations and their Web applications.