SQL Injection Overview and Risks

SQL Injection Overview

• SQL injection is a vulnerability where malicious SQL statements are inserted into input fields
• Attackers exploit this to manipulate database queries
• This can lead to unauthorized access, data breaches, and more

OWASP Top 10 Security Risks

• SQL injection is listed as a top security risk for web applications
• This vulnerability is ranked A3, indicating its significance
• Other injection vulnerabilities are also included in this list, such as command injection, XXE injection, and XPath injection

SQL Injection Statistics

• SQL injection vulnerabilities have been frequently reported
• Statistics show significant occurrences each year
• A variety of SQL injection techniques have been seen over the years
• Years 2014-2023 display data relating to SQL injection vulnerabilities

SQL Injection Background

• Web applications frequently use SQL to interact with databases
• Programmers often construct SQL queries dynamically using user inputs directly
• This approach is problematic as untrusted data can be injected into database queries
• Changing application behavior or gaining unauthorized data are examples of risks connected to this vulnerability

SQL Injection Impact

• Sensitive data can be accessed or modified
• Various administrative actions can be carried out, for example, shutting down or altering database operations
• Files can be read or changed, or other operating systems' commands can be executed from the DBMS file system
• Additional impacts such as confidentiality, integrity, availability, authentication, and authorization are also affected
• Users with attacker privilege can be created or impersonated

SQL Interfaces

• Web applications primarily interact with databases using SQL
• Programmers create interfaces using SQL, allowing apps to communicate with databases

SQL Commands

• Data Control Language (DCL): Used for controlling access rights
• Data Definition Language (DDL): Modifies the structure of the database schema
• Data Query Language (DQL): Used to extract data from the database
• Data Manipulation Language (DML): Used for manipulating data in the database

First-Order vs. Second-Order SQL Injection

• First-order SQL injection occurs when unsafe user input is immediately processed by the application
• Second-order SQL injection involves storing unsafe user input for later use in an SQL query

SQL Injection Prevention Techniques

• Prepared Statements: These statements separate query data from query structure to prevent malicious code injection
• Stored Procedures: These procedures are precompiled database objects to limit the opportunity for SQL Injection vulnerabilities
• Input Validation: Proper validation of user inputs is important. Allow-listing, an approach of only allowing specific inputs, is one option
• Output Encoding: Encode output data to prevent cross-site scripting and other vulnerabilities

Blind SQL Injection

• Blind SQL injection vulnerabilities occur when applications are vulnerable to SQL injection, but HTTP responses don't contain the query results or error details
• Determining password lengths and other database information is often possible through these vulnerabilities
• Exploiting flaws to change app logic or extract data is possible here
• Conditional responses and time delays can be used to exploit this type of vulnerability

Additional SQL Mitigation Techniques

• Least privilege: Limiting privileges assigned to database accounts prevents inappropriate actions
• Data Validation: Validating data types, lengths, and ranges can help prevent exploits
• Checking Results: Verify the received results match expected values

SQL Injection Examples

• Various scenarios illustrate attack methods such as retrieving hidden data, subverting application logic, and probing databases for usernames and passwords
• Exploiting vulnerable queries and forms is an example used to show techniques.