JSON Injection: Definition, Types, Dangers, and Prevention Tips

Quick Summary: JSON injection aims to manipulate a web app’s behavior by injecting malicious code. It allows an attacker to steal sensitive data or cause downtime. You will get a complete understanding of JSON injection, how it occurs, and ways to prevent it to safeguard your digital assets in this article. Keep reading for more information.

In the early 2000s, Java Applet and Flash were the dominating methods for server-to-browser communication. However, JSON has taken that position today because it is more flexible, language, independent, and easy to transmit over a network.

Web applications use JSON to transmit data to web servers and vice versa. While JSON ensures smooth transmission of data, it also makes web apps susceptible to cyberattacks. Attackers can take advantage of JSON injection vulnerabilities to gain access to sensitive data.

Protecting from JSON injection requires a robust security measure. Plus, you must detect web app vulnerabilities regularly to ensure it doesn’t have any loopholes that can allow an attacker to bypass security controls and access your sensitive data.

Delve into this article to learn more about this threat vector, associated risks, and tips for prevention.

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What is JSON Injection?

JSON or JavaScript Object Notation is a popular open standard file format as well as a data interchange format. Often, web applications use JSON to transmit data. It has become a medium of communication between a web application and a web server.

JSON injection is a type of attack in which an attacker can inject malicious code into a web application that uses JSON for information interchange. Web Applications that process JSON from untrusted sources or use it without validation are susceptible to these attacks.

An attacker can exploit JSON injection vulnerability to insert malicious code and carry out attacks like Cross-Site Scripting, Remote Code Execution, Server-Side Request Forgery, and more.

Types of JSON Injection Attack

JSON injection is one of those nasty injection attacks that aim to add malicious code to a web-based application. An attacker tries to manipulate application code and its behavior to achieve malicious objectives with JSON injection.

With this attack vector, an attacker can change the execution flow of a web application, which will result in exposed data. Consequently, it will lead to data loss, denial of service, data alteration, and other types of risks. There are two types of JSON injection attacks – client-side and server-side JSON injection.

Let’s check out these types below.

Client-Side JSON Injection

As the name suggests, this attack occurs on the client side. An attacker can inject malicious JSON data or files into client-side code to perform this attack. It is a DOM-based attack, which means the attacker tries to manipulate the DOM data.

Server-Side JSON Injection

Server-side JSON injection is a type of attack that affects servers. It occurs when the server processes JSON data supplied by users without proper sanitization and validation. The server fails to identify the risks of malicious scripts if it doesn’t validate inputs or sources.

How Does JSON Injection Attack Work?

Well, a JSON injection attack occurs when a web application creates JSON from unvalidated/untrusted input. An attacker can exploit this loophole to alter the execution of a web app or modify its behavior. Since JSON is used for information interchange or to store a web app’s information, an attacker can tamper with it to gain access to your sensitive data.

There are two primary reasons for JSON injections as follows:

• When data is received from an untrusted source, and it is processed (parsed) without sanitization using the “eval()” function of JavaScript on client side.
• When data is received from an untrusted source and is used directly in JSON streams without sanitization by the server.

JSON injection attacks can take place on the client side or server side. Let’s understand how server-side JSON injection works. Suppose a web app uses PHP on the server side. Now, the application stores user data in JSON format and gets username and password information without sanitization.

A JSON string is created based on the user inputs by concatenating the values as follows:

$json_string = ‘{“account”:”user”, “user”:”’.$_GET[‘user’].’”, “password”:”’.$_GET[‘password’].’”}’;

Now a malicious attacker supplies username as “John” with account type as “administrator” resulting in a JSON construct like:

{  “account”:”user”,  “user”:”John”,  “account”:”administrator”,  “password”: “xyzabcd”  }

After this, the JSON parser will find two entries for the user account and administrator account. It grants access to the last user, thereby allowing “John” to gain administrative privileges and access to the server. Consequently, the attacker gets access to sensitive server data and resources, allowing him to execute malicious code, steal information, or install malware.

What are the Dangers of JSON Injection?

While JSON facilitates communication between a web application and the server, you must take care of potential vulnerabilities that can lead to a JSON injection attack. It can put your application and its data at risk, resulting in unauthorized access and other threats. The following are the key risks related to JSON injection.

Risk of Data Integrity

Data integrity means the originality of data and its output. When there is a JSON injection attack, it can allow the attacker to compromise the integrity of an application and its data. The attacker can manipulate the semantics of JSON messages and documents.

It means an attacker can modify the information in your JSON document and gain control over your application or access crucial data. Preventing JSON injection is necessary to protect your data from unauthorized modifications and ensure that it is accurate and reliable.

Risk of Data Confidentiality

Another danger of JSON injection attack is unvalidated access to your data. Data confidentiality means safeguarding your application and its data from unauthorized access or viewing. With JSON injection, the attacker can tamper with server requests and cause it to execute malicious code.

Risk of Unavailability

An attacker can use JSON injection to cause the unavailability of your application with a DoS or DDoS attack. The attacker can gain complete control of the application and perform unauthorized actions to cause downtime.

Downtime caused by DoS or DDoS attacks will not only disrupt business operations, but it will also affect overall business efficiency. Hence, protecting your web app from this risk is crucial to ensure smooth business operations.

Tips to Prevent JSON Injection Attack

If unaddressed, JSON injection can become a critical security challenge for your organization. It can allow an attacker to not only access sensitive data but may also help them get access to privileged accounts like administrators, helping them control applications and their data. Hence, it is pivotal to stop this threat vector. The following tips can help mitigate the risks arising from JavaScript Object Notation injections.

Input Validation and Sanitization

JSON injection happens mostly due to a lack of input validation. Well, input validation is a method to evaluate user-supplied data to ensure that it doesn't contain malicious code. It ensures that the data or information provided by users via input fields, URL parameters, or any other method meets the specific standard or criteria.

Input validation is crucial to create secure JSON constructs by checking user-supplied data for specific parameters, value constraints, formatting, and type. Sanitization is also important to protect web applications against JSON injection attacks.

Sanitization involves checking inputs for special characters that can cause an application to execute arbitrary code. It entails stripping the user data of special characters or elements.

Leverage the Least Privilege

The principle of least privilege is another important method to prevent JSON injection vulnerability and avoid cyberattacks. Well, the principle of least privilege states that users must have only the necessary access rights they are entitled to instead of granting full access.

Consequently, it prevents lateral movement of an attacker that results in privilege escalation. You can take it to another level by adopting zero trust architecture, which is based on the “never trust, always verify” principle. This principle states that no user must be trusted explicitly, and authentication should be performed for every request.

It prevents unauthorized access and mitigates varied web application security risks. Zero trust architecture is helpful to defend web applications against JSON injection risks because it can prevent unauthorized users from tampering with the JSON data.

Regular Security Testing

Continuous vulnerability assessment is also helpful to prevent cyber threats like JSON injection attacks. It helps you uncover security loopholes that allow attackers to compromise web app security and steal sensitive data. With a comprehensive security audit, you can discover these hidden loopholes and address them with remediation and effective measures to safeguard your data against cyber threats.

You can also discover JSON injection vulnerability by performing a security audit on your web application. The security audit helps you understand your threat landscape, so you can create a strategic security plan to defend your web application.

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Mitigate JSON Injection Risk with ZeroThreat

JSON injection can be a critical security challenge for your web application’s security and integrity. Attackers can leverage it to steal sensitive information or even control the target application. However, you can mitigate this threat by performing security audits with ZeroThreat, which will help you discover relevant vulnerabilities.

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