Cybersecurity Awareness Month: How to Mitigate a SQL Injection Attack

A Structured Query Language (or SQL) injection attack was listed as the third-largest enterprise security risk by the OWASP Top 10 and still poses a threat to 21% of organizations, costing them millions in recoveries and reputational damage each year.^{1 2}Nevertheless, US Google searches for “SQL injection definition” have increased by 250% in the last 90 days, underscoring the growing prevalence and importance of such attacks.³

In response, application security SaaS company Indusface has detailed the potential financial impact of SQL injection attacks on organizations. Additionally, they provide best practices to help organizations effectively mitigate the risks associated with such attacks.

How costly can a SQL injection attack be for a company?

SQL injections are listed as the third critical enterprise security risk in the OWASP Top 10 and pose a significant threat to enterprise data security. The impact of a SQL injection attack can be severe as it grants attackers full control of databases and allows them to manipulate or extract sensitive information. This can result in stolen data being sold on the dark web, which can result in significant financial and reputational damage.

In addition, data manipulation can lead to business interruptions and extortion attempts. Some of the largest organizations, including TalkTalk, fell victim to an SQL injection attack and were fined over £400,000 ($522,750) after 150,000 customers had their data stolen.⁴

This highlights why developers need to implement robust protections to prevent unauthorized access and protect against data breaches.

Venky Sundar, Founder and President of Indusface, explains how companies can effectively mitigate the risks associated with a SQL injection attack:

“There are many ways to effectively prevent an SQL attack; Securing all inputs and server-side processes is the most important thing. While client-side validation is helpful, it is not sufficient against determined attackers. Here is a comprehensive 8-step approach to preventing and mitigating SQL injection attacks:

1. Implement input validation and proper error handling to secure database interactions.

By validating user input, applications can restrict data to expected formats and standards, reducing the risk of executing malicious SQL commands in SQL queries and ensuring that they conform to predefined criteria such as format, length and range. Disinfection is different; It removes or encodes potentially harmful characters from the input.

Example (with PHP and filter_var):

$username = filter_var($_POST[‘username’]FILTER_SANITIZE_STRING);

2. Use parameterized queries and prepared statements to prevent malicious SQL input.

Mitigating SQL injection attacks requires secure coding practices. Developers should use parameterized queries and prepared statements to ensure that user input is never executed as SQL code.

Another effective coding method to mitigate the risk of SQL injection is parameterized statements. These separate user input from the SQL query, eliminating the need for manual escaping and ensuring user input is treated as data, preventing potentially malicious code from executing. The database system identifies placeholders and thus secures user input during execution.

Example (with Python and SQLite):

Cursor.execute(“SELECT * FROM users WHERE username = ? AND password = ?”, (user_input,password_input))

Wildcards (?) are used instead of inserting user input directly into the SQL query for values ​​provided later. The query is executed with wildcards as the initial argument and a tuple of actual values ​​(e.g. user_input and password_input) as the second. During execution, the database securely binds these inputs as data rather than as part of the SQL query, preventing SQL injection attacks.

3. Maintain applications and databases.

SQL injection vulnerabilities in applications and databases are frequently discovered and publicly disclosed. To mitigate risk, organizations must stay current on vulnerability updates and vendor announcements and ensure that patches or updates are applied promptly.

To prevent SQL injections, all elements of a web application must be regularly monitored and updated, including database servers, frameworks, libraries, plugins, APIs, and web server software. For companies struggling with timely patch rollout, investing in a patch management solution can help reduce the workload on IT and development teams by streamlining the update process.

4. Monitor application and database interactions and communications.

Organizations should implement continuous monitoring of SQL statements in database-connected applications, focusing on activities related to accounts, prepared statements, and stored procedures. This enables timely detection of unwanted SQL statements and vulnerabilities, allowing administrators to mitigate risks by removing unnecessary components.

Integrating machine learning and behavioral analytics through tools like Privileged Access Management (PAM) and Security Incident and Event Management (SIEM) further improves protection against SQL injection and other database threats.

5. Deploy Web Application Firewalls (WAFs).

A Web Application Firewall (WAF) serves as a critical layer of security by monitoring and filtering incoming HTTP traffic, helping to detect and block potential SQL injection attempts and other malicious activity. Through customizable rules, WAFs detect specific attack patterns, providing additional protection for applications.

In organizations that face challenges such as outdated code, testing resource limitations, and frequent application updates, a WAF can be particularly beneficial. Instant code fixes aren’t always feasible for organizations, so WAFs enable virtual patching, providing temporary protection from known vulnerabilities while allowing time for proper updates.

They can also log suspicious activity and alert administrators to gain insights into potential threats and enable timely responses.

6. Use stored procedures in the database.

Implementing stored procedures can add a layer of protection by isolating the database from direct user interaction, thereby reducing the risk of certain exploits. Instead of executing SQL code directly in the database, the application triggers stored procedures that then return the results. Stored procedures also require variable binding, which further increases security by ensuring that user input is processed properly.

However, it is important to note that stored procedures are not completely immune to SQL injection vulnerabilities, especially when dynamic SQL generation is used within the procedure.

7. Patch and update your SQL servers regularly.

To maintain security and system performance, it is important to keep SQL Server up to date with the latest cumulative patches and security patches. Regular updates reduce vulnerabilities and improve system stability. However, it is important to test these updates in a non-production environment before deploying to avoid compatibility or performance issues.

Automated tools like Windows Server Update Services (WSUS) can streamline the update process, but manual testing and troubleshooting remain important practices.

If patches cannot be prioritized immediately, deploy virtual patches to the WAF. These are compensatory controls that buy your team time until they are ready to patch the code.

By staying current with patches and proactively addressing potential issues, organizations can minimize risk and ensure the ongoing integrity of their SQL Server environments.

8. Educate employees and developers about secure coding practices and attack prevention.

To further mitigate the risks of SQL injection to your organization, it is important to demonstrate to developers the potential impact of SQL injection attacks on both the database and the application. Using tools like sqlmap or sqlninja can effectively demonstrate how easily SQL injection vulnerabilities can be exploited to extract data, execute commands, or perform other malicious actions on a database.

Finally, providing real-world examples of SQL injection attacks that have resulted in significant data breaches, financial losses, or reputational damage can further illustrate the risks.