Error Based SQL Injections

An in-band injection technique allows hackers to take advantage of the database’s error output. Databases are manipulated into generating an error that informs the hacker about the structure of the database. Hackers utilize one of the communication channels of the server to launch an attack and retrieve information using in-band injections. Force data extraction requires using a vulnerability. Usually, the vulnerability allows code to show an SQL error from the server in place of the required data. Hackers can understand the structure of the database from this error.

Example of Error-based SQL Injections:

Adding SQL syntax to user input: In this SQL injection, a hacker inserts a malicious query to get an error that displays a message containing sensitive information about the database. A hacker might try writing a SQL command in any input field like a single quote, double-quote, or any other SQL operator like OR, AND, NOT.

For Example, for a URL of a site that takes a parameter from the user,

 then in that case: https://www.example.org/index.php?item=123

Then here attacker can try inserting any SQL command or operator in the passes value,

 as: https://www.example.org/index.php?item=123′

In this case, a database could return some error like this, If you have an error in your SQL syntax, check the manual corresponding to your MySQL server version for the right syntax to use near “VALUE.” This message gives the attacker information like the database used in SQL, the syntax that caused an error, and where the syntax occurred in the query. For a professional hacker with experience, this will be enough to tell him that the server is insecurely connected to a database and can plan additional SQL injection attacks that will cause damage. An attacker can try several queries using commands like grep extract in input fields and see adding which commands return an error.

Prevention from Error-Based SQL Injection:

1. Prepared statements: The most secure way to write the database queries is using prepared statements with variable bindings. It is better because it uses parameterized queries, as working with dynamic queries is tricky. The developer must define all the SQL code beforehand, and then each parameter must be passed to the query. This method prevents almost all SQL injection attacks, as it stops hackers from changing the query’s intent and creates a separation between user input and data. This withstands better against the malicious queries entered by the users. In sporadic cases, this method will affect the server’s performance; in that case, other methods can be used.

2. Stored Procedures: This is another way to stop the attackers from attacking the system, and if it is implemented correctly, it can completely erase the possibility of SQL injections. For the stored procedure, whenever an application needs SQL queries, then they are fetched from the database itself as the SQL queries are defined and stored there for implementing the stored procedure.

3. Least Privilege: All the permissions given to the Bluetooth devices must be checked; only the necessary ones should be allowed by the device. For Example, an application must be permitted to access the database to manipulate the stored data. This reduces the risks related to SQL injection. Many normal-looking apps sometimes request access to the sensitive data present in the database. So it is better to reduce the apps’ permissions and allow only the important ones.