Top Tips for Preventing SQL Injection Attacks
In the aftermath of the colonial pipeline attack and other high profile cases, IT teams may scramble to strengthen the protection of their endpoints. But members of the developer community know that security vulnerabilities don’t start and end there; write code incorrectly or with insufficient security, and you are also coding in future web attacks.
Web vulnerabilities are an issue that plagues even the largest tech companies. They cover a whole host of different coding issues, but the examples above include a very specific type.
A zero trust approach
SQL injection is one of the most dangerous and common vulnerabilities out there, but luckily there are several best practices developers can follow to ensure there are minimal loopholes in their armor.
The first is to ensure that client-side input validation is not the only line of defense. This validation is a great tool to improve the user experience, but it does not work as a security mechanism.
Developers should also think carefully about the privileges of database users. All SQL injection attacks are harmful, but some are more harmful than others: accessing user information is one thing, but changing or deleting it is another.
To minimize the impact of an SQL injection, developers should be strategic about an application’s privileges on a database. Does a specific application really need to be able to read, write and update all databases? Does it need to be able to truncate or drop tables?
In addition to not allowing each application to rule freely over a database, it is also not recommended to have a single database user for an application. Making multiple database users and connecting them to specific application roles work the same way fire doors work to contain a fire: this prevents an attacker from quickly taking over a fire. entire database.
Settings are the best defense
An essential way for developers to protect themselves is to use prepared statements and query parameterization. Many languages come with built-in features that help prevent SQL injection. So, when writing SQL queries, you can use a prepared statement to compile the query.
Prepared statements can be used to perform query parameterization, which limits the SQL statements that can be entered: a developer creates a base query with placeholders, then user-supplied parameters can be securely attached to these reserved spaces. When using a prepared statement and parameterized queries, the database will first create the query execution plan based on the query string with placeholders, then send the parameters (untrusted ) to the database.
As the query plan is already created, the parameters no longer influence this and this completely blocks the injection. The statements prepared with the parameters of the queries are therefore the best defense against SQL injection.
Parameterization is also essential when working with stored procedures. Many people think that working with stored procedures is a good way to prevent SQL injection, but this is not always the case. Like any SQL query created in an application, a stored procedure can be maliciously injected. Therefore, as with SQL queries, developers should parameterize queries in their stored procedure, rather than concatenating parameters, to protect against injection.
However, in some situations, prepared returns are not available. If a certain language does not support prepared statements, or if an older database does not allow developers to provide user input as parameters, input validation is an acceptable alternative.
Teams should ensure that input validation is based on the permission list and not the block list – by using a well-managed library or by creating a rule that describes all allowed patterns with, for example, a regular expression . Of course, even though prepared instructions are available, validating the inputs is a must.
Multi-layered security and rigorous control
In addition to parameterization and input validation, developers should consider using an object-relational mapping (ORM) layer to protect against injection. This turns data in a database into objects and vice versa, reducing explicit SQL queries and therefore the risk of SQL injection attacks. However, it should be noted that vulnerabilities can still be created in ORM libraries if faulty or outdated versions of Sequelize or Hibernate are used, so developers should be vigilant.
Ultimately, whatever security policies are deployed, a strict review system must be in place to review the code and report any vulnerabilities. Code review and pair programming allow this, but with manual review processes there is always room for error. For the highest levels of security, developers should turn to specially designed scanning tools to automatically check for SQL injection vulnerabilities and alert them to any weaknesses in their code.
SQL injection attacks are a dangerous online threat, but they can be fought. With a zero-trust approach, the use of prepared instructions and parameters, and a rigorous code verification process, developers can block any injection attempts. As cybercrime grows alongside digitization, it’s more important than ever that developers put security at the heart of their code.