Query Injection

Simple Definition for Beginners:

Query injection is a type of cyber attack where hackers insert malicious code into a query to gain unauthorized access to a database.

Common Use Example:

When a hacker inputs special code into a login form to bypass authentication and access user data, they are performing a query injection attack.

Technical Definition for Professionals:

Query injection, commonly known as SQL injection (SQLi), is a code injection technique used to attack data-driven applications. Attackers insert or manipulate malicious SQL code in a query to access or manipulate the database. Key aspects include:

• Types of SQL Injection:

o In-band SQLi: The attacker uses the same communication channel to execute and retrieve results.

• Error-based SQLi: The attacker triggers errors to retrieve database information.
• Union-based SQLi: The attacker uses the UNION SQL operator to combine results from multiple queries.

o Inferential SQLi (Blind SQLi): The attacker sends payloads to observe server behavior and infer information.

• Boolean-based Blind SQLi: The attacker manipulates SQL queries to return true or false responses.
• Time-based Blind SQLi: The attacker executes SQL queries that cause time delays to infer information.

o Out-of-band SQLi: The attacker uses different channels to execute queries and retrieve results.

• Vulnerable Points:

o User Inputs: Forms, search fields, login pages, and URL parameters are common points of attack.

o Dynamic SQL Queries: Queries that construct SQL statements using user inputs are highly vulnerable.

• Potential Impacts:

o Data Theft: Unauthorized access to sensitive data such as user credentials, personal information, and financial records.

o Data Manipulation: Modification or deletion of database records.

o System Compromise: Executing administrative operations on the database, leading to full system control.

o Denial of Service (DoS): Overloading the database with queries to make it unavailable.

• Prevention Techniques:

o Parameterized Queries (Prepared Statements): Using placeholders for inputs to separate SQL logic from data.

o Stored Procedures: Executing predefined SQL code on the server side to avoid direct user input in queries.

o Input Validation: Ensuring all user inputs conform to expected formats and values.

o Escaping Inputs: Properly escaping special characters in inputs to neutralize malicious code.

o Least Privilege Principle: Restricting database user privileges to limit the impact of potential attacks.

• Detection Tools:

o Web Application Firewalls (WAF): Filtering and monitoring HTTP requests to block malicious activities.

o Intrusion Detection Systems (IDS): Detecting and responding to suspicious activities in the network.

o SQL Injection Scanners: Automated tools like SQLMap to identify vulnerabilities in web applications.