Imagine walking up to the information desk at a busy airport and, before you can ask about your flight, someone else interjects with a question of their own. It’s annoying and rude, but it’s not dangerous.
When cybercriminals do something similar with the queries posed to a relational database, however, the results can be devastating. These SQL injection attacks need to be identified and stopped in their tracks.
Understanding SQL Injection (SQLI)
While it’s a common form of hacking, SQL injection attacks continue to happen often enough that everyone in a business should have a basic understanding of what they are and how they work.
Definition and explanation of SQL Injection
Every time you search for, update or retrieve data in a relational database, the application you’re using is probably based on queries written in structured query language (SQL). Normally these are routine processes that we can take for granted.
When cybercriminals spot vulnerabilities in an application, though, they can alter SQL queries or inject them with malicious code.
A successful SQL injection attack can give threat actors unauthorized access to a database and the ability to execute tasks or even steal data.
How Does SQL Injection Work?
Part of what makes combatting a SQL injection attack difficult is that cybercriminals can come at them in more than one way.
An in-band SQL injection attack, for instance, will involve inserting malicious code into any available field. When a database processes this input, attackers can circumvent passwords and gain authorized access to information.
Error-based SQL injection attacks take a different approach. Threat actors will ask the database a question that comes back with an error, as well as information about the backend and its structure.
Blind SQL injection attacks can be executed in one of two ways. For example, cybercriminals can inject code into a web application’s input field to return a true or false (a.k.a. Boolean) result). This could help them determine whether a user’s ID exists in a database, or if it contains other vulnerabilities.
In a time-based blind SQL injection attack, threat actors can determine whether a query’s result is true or false by forcing the dataset to wait for a number of seconds before responding. Both of these are sometimes referred to as inferential SQL injection attacks, since no data is returned to the web application.
Common methods used in SQL Injection attacks
SQLI attacks can also vary in how cybercriminals inject their data into a query.
Using forms is a common approach, given how many web applications use them and allow user input to be submitted.
Cookies can also be modified to “poison” SQL queries sent to the database.
If HTTP headers are accepted among a web application’s input, these can also be faked and injected with arbitrary code.
Things get even more complicated when attackers inject a table row or other content that appears trustworthy into a query. Organizations might not be aware of these so-called second-order SQL injection attacks for some time, because they might not be executed immediately.
Potential consequences and risks of SQL Injection
Organizations can’t afford to overlook SQLI attacks. They pose risks ranging from identifying database users and stealing data to destroying it entirely.
In other scenarios SQLI attacks have allowed rogue actors to make themselves database admins and interfere with everyday processes, like voiding transactions and altering information in an online account.
SQL Injection Examples
SQLI attacks have been so prevalent that many specific incidents have been well-documented, allowing organizations to learn how to protect themselves from similar situations.
The impact of successful SQL Injection
Beyond the risks and consequences mentioned above, the most typical impact of a successful SQL injection is accessing user credentials. This opens the door to a wide range of potential opportunities for data to be stolen or misused.
Real-world case studies and notable incidents
Some of the best-known real-world case studies of SQLI attacks involve household names such as Sony Pictures Entertainment and Marriot Hotels.
More recently, however, researchers discovered a critical flaw allowed hackers to expose more than a million WordPress sites to SQL injection. A hacker group dubbed Gambleforce, meanwhile, has waged a string of SQLI attacks on firms across the Asia-Pacific (APAC) region, stealing information from government agencies, retailers and other organizations.
The ongoing wave of SQLI attacks has prompted the FBI and CISA to issue a “secure by design” alert in March 2024, urging organizations to take steps to curb vulnerabilities and related risks.
How to Prevent SQL Injection
Fortunately, there are well-established cybersecurity practices your organization can use to defend itself against SQLI attacks. Whether you work in IT security or not, these are all well worth knowing and adopting.
Identifying vulnerabilities and weak points in your application
Cybercriminals tend to look for web applications where it is clear the organization running it has failed to properly validate and sanitize the data it uses or allows the application to accept data from an untrusted source.
Rather than force IT security teams or developers to manually check for holes across every web application, many organizations use third-party vulnerability scanners that automate this process. These tools tend to conduct a variety of tests to look for vulnerabilities, such a single quote character that produces errors or anomalies. They may also try to spot time response deficiencies and out-of-band network interactions.
Best practices for secure coding and input validation
Checking the input data to ensure that it is complete, valid and consistent is the foundation of secure coding. This includes examining data by type, range and format.
All input requirements should be defined up front, and developers should look at how an application will handle missing values. Most experts also recommend using standard libraries on a client-side system and classifying all data sources into trusted and untrusted segments.
Using parameterized queries and prepared statements
Whenever untrusted data appears as input within a query, using prepared statements can prevent others from interfering with the query structure.
The variable binding in this approach forces the database to make a distinction between an application’s code and its data. Cybercriminals could still insert SQL commands into a query, but they won’t be able to change the query’s intent.
Mitigating SQL Injection Risks
There are other steps beyond secure coding that can prevent SQLI attacks from happening, or reducing the impact when they do. Make sure your IT security team is already:
Implementing a robust web application firewall (WAF)
Just as a retail store might install a camera in front of its entrance and exits, a WAF monitors all the traffic coming into and out of the corporate network. They help prevent SQLI attacks by adhering to a set of pre-defined policies, such notifying admins when traffic behaves in an unusual or unacceptable way. A WAF can also block or modify traffic based on these policies.
The better you understand which web applications you want to protect, the URLs you want block or other rules you want in place, the better you’ll be able to configure a WAF to keep SQLI attacks at bay.
Regularly updating and patching your database software
Application vendors are constantly at work improving the security of their products and include critical fixes as part of the regular updates they make available to their customers. This is low-hanging fruit from a cybersecurity perspective and should be a standard part of any IT department’s routine.
Updates and patches are often ready to install with just a few clicks of a button on many application dashboards. Of course, make sure to understand how updates will affect the performance of your applications and those with which they’re integrated. It’s also a good idea to have regular backups of your data before updates and patches are installed.
Conducting security audits and penetration testing
Most organizations get so busy tackling their day-to-day priorities that it’s easy for security gaps to appear and get wider over time. It could be a database that was misconfigured, the use of weak passwords to access critical applications or unpatched software as we talked about in the previous section.
Security audits allow IT to take a step back and review all the potential vulnerabilities and risks that might be otherwise overlooked.
Penetration testing, meanwhile, is a way to simulate the kinds of attacks threat actors might attempt, including SQL injection. Pen testing is a way to see how far attackers could get into the network and the scope of damage they could cause unless preventative measures are taken.
The Importance of Educating Users on SQL Injection
As always, knowledge is power, especially when you’re talking about providing essential team members with greater knowledge about SQLI attacks and their role in avoiding them.
Raising awareness among developers and system administrators
Those coding web applications and running tools like a WAF may already have a baseline understanding of SQL injection attacks. What they may not know is the extent to which your organization has been left vulnerable and exposed due to common practices.
Developers can help bolster your defenses by using the principle of least privilege when provisioning SQL database accounts, for example. A WAF admin might decide to tighten policies based on a greater awareness of how likely the organization could be targeted with malicious code.
Training employees to recognize and report potential vulnerabilities
Even those on the frontline with little technical background can help raise the alarm about potential SQL injection.
When they notice unexpected errors or erratic performance in web applications, for example, staff should know who to contact within IT and what kind of details are ideal to assist with further investigation. This can save valuable time and limit the extent to which an SQLI attack allows threat actors to gain access to a database.
Creating a culture of security and ongoing education
Employees in organizations where security is deeply rooted in the culture also tend to take preventative actions that get in the way of SQLI attacks.
Using strong passwords, backing up data, not sharing credentials and avoiding untrustworthy sites are all part of defending against SQL injection and other potential threats.
How LastPass Safeguards User Data from SQL Injection
SQL injection attacks are just one example of the cyber threats LastPass was designed to address.
Overview of LastPass's security features and measures
Based on a zero-knowledge approach where your data remains secret, LastPass provides a single source to manage all your credentials and security autofill on forms and devices.
LastPass also offers multi-factor authentication that contributes to a defense-in-depth approach to safeguarding critical assets like web applications and databases.
Continuous improvement and commitment to security
LastPass also follows the best practices outlined in this article, including engaging with trusted third parties to perform regular security audits and following responsible disclosure policies to make users aware of any vulnerabilities.
Put your SQL injection attack fears to rest. Start your LastPass trial today.
FAQ
How do I prevent SQL Injection in PHP?
PHP is a server-side web scripting language, while SQL is a language for interacting with Relational Database Management Systems (RDBMS) like MySQL. The mysqli_connect() function establishes a connection between PHP and MySQL to enable CRUD (Create, Read, Update, Delete) operations with PHP scripts. Both PHP and SQL are used to create dynamic web content. For example, PHP can execute SQL queries to help with implementing shopping cart functionality on an ecommerce platform or fetching product information to display on an online catalog.
To prevent SQL injections in PHP, you can implement several protective measures such as: · Using parameterized queries and prepared statements to separate SQL queries from user input, so malicious input can’t be executed as SQL commands
· Implementing user input validation or sanitation to ensure only authorized data formats enter the application workflow, preventing injections of malicious code
· Ensuring regular updates and patches are applied for PHP versions and SQL database software
· Conducting security audits and penetration testing to identify security gaps
· Employing a WAF (web application firewall) to filter malicious traffic
How do SQL injections exploit web applications?
SQL injections exploit web applications by inserting or “injecting” malicious code into user inputs. This alters how the original query behaves when executed by the database. Attackers exploit the lack of input validation or sanitization to insert the malicious code and perform unauthorized actions like modifying or retrieving sensitive data. For example, in-band injections send malicious SQL queries directly through the application interface to retrieve user information.
Meanwhile, error-based injections exploit database error messages, allowing the attackers to uncover information about the database structure to craft more sophisticated attacks.
How can you detect an SQL injection vulnerability?
You can detect an SQL injection vulnerability by: · Using Microsoft Defender for SQL to continuously scan and monitor SQL servers for security vulnerabilities · Using automated tools like sqlmap to find and exploit database vulnerabilities · Manually inserting common SQL injection payloads into user input fields to see how the application handles unexpected inputs. This helps pen testers assess the effectiveness of the application’s user input validation process.
