As the cybersecurity landscape becomes increasingly complex, it’s essential for organizations to stay informed about the tactics most likely to be used against them. In 2023, SQL injection attacks accounted for 23% of all critical web application vulnerabilities globally, making them the most common type of attack. Although SQL injection attacks are relatively simple and can be prevented through thoughtful coding practices, they can still cause significant damage to your database and IT environment. Here’s how threat actors perform SQL injection attacks, the tactics your development team can use to remediate SQL-related vulnerabilities, and the strengths and weaknesses of each approach.
SQL injection attacks occur when developers create dynamic queries that rely on concatenation and user-supplied inputs to access databases. When this happens, malicious users can deliberately input (inject) harmful code that the application executes at runtime.
For example, suppose an application requires a username and password to complete an access request. An example code snippet might be:
select id
from users_table
where username='$username' and password='$password
An attacker could deliberately input a false username and password, potentially gaining access to the database even if the credentials are incorrect. Once a connection is established, they could attach a command that either damages or extracts sensitive data.
Since the dynamic query uses concatenation, it would pick up the additional script and process it along with the false information. The result is that the system executes the malicious code, allowing attackers to:
By simply injecting defective scripts, SQL injection attacks exploit vulnerabilities in dynamic code that hasn’t been properly sanitized, taking advantage of flaws that could have easily been avoided.
SQL injection attacks are among the simpler forms of cyberattacks, but they are unfortunately all too effective. Here are the methods and commands that make up a SQL injection (SQLi) attack, along with examples of how one occurs.
SQLi attacks rely on the target system to do much of the work. While attackers may need to gain some information about the system or make assumptions about its structure, this information is often easy to obtain.
For example, an attacker can still gain access to a system by including the command “X” OR 1 = 1 in the input, even if they enter incorrect values. Since the condition 1 = 1 is always true, any database structure that picks up this entry as a command could grant access to the attacker.
Some systems may also display error messages alerting the user that they entered an incorrect value and explaining why the error occurred. These error messages, while informative for legitimate users, can also provide useful information to attackers about critical database features and how they can be exploited.
Many applications also consist of open-source code, which is widely available to the public. After attackers either guess certain features of the system or gain insights from error messages, they can often identify the open-source code used to build the product. They can then examine the code online to search for further vulnerabilities. Whether by guessing, by error messages, or by scouring open-source platforms, attackers can quickly find ways to penetrate dynamic database queries.
Attackers can use several SQL commands to alter or exfiltrate data. Some of the most common SQLi commands include:
Directly inputting defective text is one type of SQLi, but there are other variations as well. Some common types of SQLi attacks include:
The key to reducing your vulnerability to SQL injection attacks is to separate all inputted text from your code. The most fundamental way to achieve this is by avoiding dynamic queries that use string concatenation. Here are three additional methods:
Multiple frameworks and standards, such as OWASP, provide comprehensive tactics to harden code against SQLi attacks. Consult these resources as you develop your SQLi defense strategy. Code security software can also help identify vulnerabilities within open-source code, further strengthening your SQLi defense posture.
SQL injection attacks are relatively simple in nature, yet they make up the largest portion of vulnerabilities in many tech stacks. The solution is to distance your code from the SQL as much as possible. Prepared statements, stored procedures, and input validation can help achieve this. Each tactic has its own strengths and weaknesses, so consider which one best fits your operations.Code security software can help you reduce SQL injection vulnerabilities in both proprietary and open source code, adding another layer to your defenses. Kiuwan’s software composition analysis (SCA) tools are designed to remediate open source code vulnerabilities, so contact us to request a demo.
