Security Vulnerabilities in Java Applications

The Common Vulnerabilities and Exposures (CVE) is a publicly accessible database maintained by the MITRE Corporation. It serves as a catalog of known security vulnerabilities and exposures found in software systems. Each vulnerability in the CVE database is assigned a unique identifier and provides essential information, such as the affected software versions and the flaw’s severity.  

Third-party vulnerabilities have led to numerous high-profile security breaches. As such, using Software Composition Analysis (SCA) tools to scan your project for flawed dependencies is a good practice. An example of such a tool would be OWASP Dependency-Check. To mitigate the risk, dependencies should be regularly checked and updated if needed. 

Java applications are vulnerable to various types of attacks that can compromise their security and functionality. However, covering all the possible Java application vulnerabilities is beyond the scope of a single article. Therefore, we will focus on some of the most common ones in the following paragraphs.

Cross-site scripting (XSS) is a web security vulnerability where attackers inject malicious scripts into web pages that other users view. These scripts are then executed by the victim’s browser, allowing the attacker to steal sensitive information, manipulate page content, or perform other malicious actions on behalf of the victim. There are three common types of XSS attacks: 

• Stored XSS: The malicious script is permanently stored on the target website, typically in a database, and is served to users when they visit the affected page. 
• Reflected XSS: The malicious script is embedded in a URL or input field, and the website reflects it to the user in the page’s response. The user’s browser then executes the script. 

• DOM-based XSS: The client-side scripts modify the web page’s Document Object Model (DOM), leading to the execution of the attacker’s code. 

To prevent XSS attacks from achieving success, introduce input validation and output encoding: Ensure that all user inputs are adequately validated/sanitized on the server side and that any data displayed to users is properly encoded (HTML-encoded, URL-encoded) to prevent script injection. It’s a good idea to use libraries that automatically handle input validation and output encoding to minimize human error. Consider also employing a Content Security Policy (CSP) to restrict the sources of content that a web page can load. This can prevent the execution of scripts from unauthorized domains. 

SQL injection is a type of cyber attack where malicious SQL code is inserted into a web application’s input fields or parameters to manipulate the application’s database. This is possible when the application fails to properly validate and sanitize user inputs, allowing an attacker to execute arbitrary SQL commands and potentially gain unauthorized access to sensitive data, modify data, or even destroy the database. 

To prevent SQL injection attacks, you need to separate the SQL code from the user’s input. One way to achieve it is by using parameterized queries/prepared statements instead of dynamically building SQL queries using string concatenation. If you must include user input in dynamic queries, make sure to escape the input properly using database-specific escape functions to neutralize potential SQL injection attempts. As with XSS, you should also introduce input validation/sanitization to reject special characters or SQL keywords.  

Cross-Site Request Forgery (CSRF) happens when an attacker tricks a user’s web browser into making unauthorized requests to a different website on which the user is authenticated. This attack is possible when the target website does not correctly validate the origin of incoming requests, allowing the attacker to forge a request that appears legitimate to the target website. The steps involved in a CSRF attack are as follows: 

• The user visits a malicious website or clicks on a link the attacker has crafted. 

• The malicious website sends a request to a different website where the user is authenticated, often using the user’s stored cookies or other authentication tokens. 
• The user’s browser, unaware of the malicious request, executes it as if it were a legitimate action initiated by the user on the target website. 

Check if your framework (for example, Spring Security) has built-in CSRF protection, and ensure it’s not disabled. If your solution doesn’t provide this by default, implement CSRF tokens and add them to all state-changing requests. 

This severe security vulnerability plagues many web applications and occurs when an application’s access controls and authorization mechanisms are improperly implemented or enforced. It means that users can gain unauthorized access to restricted resources or perform actions they should not be allowed to perform. For instance, a user with basic privileges might be able to access sensitive information meant only for administrators or even modify critical data without proper authorization. Some pointers on how to address the problem: 

• Conduct activity audits on servers and websites to catch any suspected events. 
• Introduce the least privileged approach; each role should be granted no more access than it needs to perform its intended tasks. 
• Disable unused access points. 

Java’s prevalence in the software industry makes it an attractive target for malicious actors seeking to exploit security vulnerabilities. Understanding the common vulnerabilities in Java applications, leveraging the CVE system, and addressing third-party risks are essential steps in fortifying the security of Java-based projects. By adopting secure coding practices, conducting regular security assessments, and staying vigilant about potential threats, developers and organizations can enhance the resilience of their Java applications in the face of evolving security challenges.