When a string is written in the code instead of in a table in the database, it is referred to as “inline SQL”.
The best way is to use string objects to build a query based on user input from the front end. Inline SQL exposes the command to SQL injection.
The outcome can have catastrophic repercussions on the server including massive data breach.
Example
The code below is an example of an inline structure.
$query = 'select usrnme, passwrd from User where user_id='. $_POST['user_id'];
Here user_id is taken from the textbox.
This technique leaves the door open for attackers to attack. Using this query with SQLi, an attacker could potentially gain access to the administrator’s credentials.
What are the impacts of inline queries SQL injection (SQLi)?
Inline queries SQL injection (SQLi) is a serious web vulnerability that allows attackers to inject malicious SQL code into a web application.
This can have several devastating consequences, including:
1. Data breaches
Attackers can use SQLi to gain unauthorized access to sensitive data, such as credit card numbers, Social Security numbers, and personal information.
2. Data manipulation
Attackers can modify, delete, or corrupt data stored in the database. This can lead to loss of business, financial damage, and reputational harm.
3. Website defacement
Attackers can use SQLi to deface a website, replacing its content with malicious or offensive material.
4. Denial-of-service (DoS) attacks
Attackers can use SQLi to overwhelm the database with requests, causing the website to become unavailable to legitimate users.
5. Remote code execution
In some cases, SQLi can be used to execute arbitrary code on the web server. This can give attackers complete control over the server, allowing them to install malware, steal data, or launch further attacks.
How can you prevent inline queries SQL injection (SQLi)?
There are several ways to prevent inline queries SQL injection (SQLi), which is a common web vulnerability that allows attackers to inject malicious SQL code into a web application.
Here are some of the most effective methods:
1. Use parameterized queries
Parameterized queries, also known as prepared statements, are a secure way to execute SQL queries that include user-supplied data.
Instead of concatenating user input directly into the SQL query, parameterized queries separate the query structure from the data values.
The data values are then treated as literal values, which prevents them from being interpreted as SQL code.
2. Use input validation
Input validation involves checking and sanitizing user input before it is used in a SQL query.
This can help to prevent malicious code from being injected into the query, even if parameterized queries are not used.
Common input validation techniques include whitelisting, blacklisting, and escaping special characters.
3. Use stored procedures
Stored procedures are precompiled SQL statements stored on the database server.
When a stored procedure is called, the database server executes the precompiled code, which prevents any user-supplied data from being injected into the query.
4. Use a Web Application Firewall (WAF)
A WAF is a security device that can be used to filter and block malicious traffic, including SQL injection attacks. WAFs can be deployed as hardware appliances, software applications, or cloud-based services.
5. Keep software up to date
Software vendors often release patches and updates that fix known SQL vulnerabilities. It is important to keep all software, including web applications and database servers, up to date with the latest security patches.
6. Educate developers
Developers should be aware of the dangers of SQLi and how to prevent it. They should be trained to use secure coding practices, such as parameterized queries and input validation.
7. Penetration testing
Penetration testing is a process of simulating an attack on a system to identify and exploit vulnerabilities. This can help to identify SQL vulnerabilities that may not be detectable by other methods.
By following these practices, web developers can help to protect their applications from SQLi and other web vulnerabilities.
