January 21, 2022

Rohit Rawat


Java is among the most widely used programming languages in the world. The fact that almost half of enterprise applications use Java proves this point. Everyone believes Java to be somewhat safe because it is a server-side language. There are still many ways to attack and gain access to information that you want to keep secret.


In this article, we will discuss the types of vulnerabilities in Java that you must be aware of.

Java Vulnerabilities and How to Overcome Them

1. Unpatched Libraries

One of the reasons why your application might be at risk is because of unpatched libraries. Hackers might exploit the vulnerabilities in Java libraries, circumventing security measures in other places. 

They can also utilize information sources to find possible flaws. That includes the National Vulnerability Database, the United States Computer Emergency Readiness Team (US-CERT), the Common Vulnerabilities and Exposures (CVE) Database, and others. This way, they can introduce nearly any weakness.


Make sure that all the components are up-to-date and patched. Keep an eye out for reported vulnerabilities so you can take action quickly. Use a dependency manager to set a minimum version for any dependencies that are listed more than once. Prevent information such as version information from leaking from systems and services. 

If you are not able to patch or replace a vulnerable library, make sure you take compensatory measures. This includes setting up network firewalls, intrusion detection systems (IDS) or intrusion prevention systems (IPS), or putting application firewalls in place.

Before selecting components, always conduct research on the top Java vulnerabilities. Store these results in a central location along with lists of libraries that have been found to be at risk. Make sure that all development teams have access to this information.

By making sure that developers don't use these components by accident, this will help fix vulnerable libraries quickly. Carefully think about the consequences of any vulnerabilities you find. The risk may be significantly higher than usual in certain circumstances.

2. Exposed Servelet

This is one of the most significant Java vulnerabilities. This application is set up to provide a management interface. Developers do not require authentication/access restrictions to see this interface. Unauthorized hackers use this interface to get access to unwanted server functions. 

When an app says "internal only," it's less likely to show that it needs access to the internal network. Therefore, exposing unauthenticated administrative functions to the internal network is not secure. Developers must treat it as a vulnerability. 


It is best to remove the highlighted snippet from the web.xml file before production. Neither the AdminServlet nor the SOAPMonitorService provide appropriate authentication mechanisms. Therefore, the only safe solution is for the Java development company to disable them.

3. Excessive Permissions

With custom permissions, an application can use its API to access hardware-level features. The Java application development services provider also needs permissions. The API allows these distinct programs to utilize sensitive functionality. They do that without having to go through the typical prompting processes. Hackers might exploit this API to gain access to such functionality. 


Applications should only ask for the permissions they need to do what they say they are going to do. The app shouldn't ask for permissions that it doesn't need and that hackers could use against it. You must prompt the user to withdraw rights that they no longer need.

4. Cross-Site Scripting (XSS)

Attackers sometimes put harmful client-side script or HTML in a form or query variables that are sent to a site through an interface. That way, the attackers send the harmful material to an end-user. This is known as cross-site scripting (or "XSS"). 

  • Persisted Cross-Site Scripting occurs when one user (the attacker) supplies the content and keeps it in their database. The database then presents this content to another user (the victim). 
  • Reflected Cross-Site Scripting is a technique in which an attacker persuades a victim to submit the contaminated data themselves. They do that through email or a link on an attacker-controlled website. Because of the technique it uses, it is amongst the top Java vulnerabilities.

With XSS, an attacker can send harmful files or other content to a user who doesn't know about it. The end user and their browser don't know that the content was not made by a trusted website. 

The web browser stores any cookies, session tokens, or other sensitive information that the site uses. The malicious script then accesses this sensitive information. These programs can even rewrite the HTML page's content. 

Phishing attacks, identity theft, website defacement, denial-of-service attacks, and other attacks can all result from this. This makes XSS attacks one of many significant Java vulnerabilities.


HTML- or URL-encoding all output data, regardless of its source, is the most reliable way of repelling most XSS assaults. This assures that contaminated data has no impact on the output from any source. That includes user input and information shared with other apps or coming from third-party sources. Developers eliminate the need for time-consuming data flow analysis. 

Consistently encoding all output data makes the application considerably easier to audit. It's important to keep in mind that encoding must work in many different output contexts, such as HTML, CSS, and JavaScript. Sometimes, a single method of encoding won't be enough to stop XSS vulnerabilities. 

In Conclusion

The above-mentioned issues are a few types of vulnerabilities in Java. To make a safe application, the developers must have complete knowledge of the vulnerabilities and their workarounds. 

The developers of our Java web application development company are well-versed in the programming language. With years of experience and knowledge, they are aware of all the Java security issues and the fixes that strengthen security. If you want to create an application that is safe and robust, contact us at any time. 

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