Enforcing least-privilege access, sanitizing user inputs, and restricting database procedures can help prevent SQL injection and subsequent data breaches.
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Structured Query Language injection (SQLi) is a code injection attack that allows attackers to retrieve, manipulate, or destroy sensitive information located in SQL databases. These attacks work by inserting specialized commands into SQL query fields; when executed, the commands may enable attackers to spoof the identity of legitimate users, view or retrieve protected data, and even gain root access to servers.
Often, attackers carry out SQLi by exploiting vulnerabilities in application programming interfaces (APIs) that cannot properly differentiate between legitimate and untrusted code. Without the ability to detect altered commands or queries, these APIs can be used to execute malicious requests, such as bypassing web application firewalls (WAF) or authentication measures.
Typically, SQLi is performed using one of three methods:
To see real-world examples of benign and malicious SQL queries, read What is SQL injection?
While SQL injection is one of the most prevalent API threats, it can be effectively avoided with the right prevention strategies. Helpful approaches for preventing SQL injection include restricting database procedures, sanitizing database inputs, and enforcing least-privilege access.
SQL injection largely depends on an attacker’s ability to manipulate data inputs and database functions. By restricting these inputs and limiting the type of database procedures that can be performed, organizations can minimize the risk of unauthorized or malicious queries. Ways of doing so include:
User inputs into any SQL database should be regularly monitored, validated, and sanitized to eliminate malicious code. Input validation ensures that data is properly inspected and formatted according to predetermined criteria, while input sanitization modifies (or “sanitizes”) the input by removing invalid or unsafe characters and reformatting it as necessary. Ways of ensuring input validation include:
Least-privilege access is the principle of giving users only as much access to protected resources as their role requires. For example, this may mean limiting the number of users who are granted administrator-level privileges to a database, or even giving users temporary admin-level access that can later be revoked.
Restricting user access on a role-based level also helps minimize the impact of a breach, as attackers who breach a database using stolen credentials will be similarly limited in their ability to view, modify, steal, or destroy protected data. For the same reason, organizations should limit shared access to databases across multiple websites and applications.
Cloudflare helps organizations improve their resilience against SQLi attacks with a powerful application and API security portfolio: