Top 5 Java Security Vulnerabilities to Watch For

By NIIT Editorial

Published on 16/06/2023

Java is a popular programming language that is used to create many different kinds of programmes. As fraudsters often target Java due to its widespread adoption, maintaining its security is of paramount importance. The security of a Java application is crucial since it might jeopardise the accessibility, integrity, and privacy of important data. This article will go through the top 10 Java security problems and how they may be avoided.


Table of Contents


  • Deserialization Vulnerabilities 
  • SQL Injection Vulnerabilities 
  • Cross-Site Scripting (XSS) Vulnerabilities 
  • Cross-Site Request Forgery (CSRF) Vulnerabilities 
  • Authentication and Authorization Vulnerabilities  
  • Conclusion


Deserialization Vulnerabilities


Data that has been serialised (that is, data that has been saved in a certain format that can be readily sent or stored) may be deserialized by reversing the serialisation process. When deserialization is used by an attacker, they may get access to sensitive data, execute arbitrary code, or change the functionality of the application. This flaw allows attackers to introduce malicious payloads into the application because of poor input validation and sanitization during the deserialization process.


Examples of Deserialization Attacks


  1. Remote Code Execution (RCE)

An adversary may construct a malicious payload to overcome the server's security measures and run arbitrary code.


  1. Denial of Service (DoS)

A crash or considerable delay in performance may be caused by an attacker providing malicious data to be deserialized.


  1. Data Tampering

Serialized data is vulnerable to manipulation by an attacker who may use it to gain unauthorised access to the system or change the application's behaviour.


Methods for Preventing Deserialization Vulnerabilities


  1. Input Validation and Sanitization

Deserialization should only be performed on validated and sanitised input to guarantee only reliable data is used.


  1. Implement Object Whitelisting:

Limit the potential for malicious code execution by using a whitelist of deserializable objects.


  1. Avoid Deserialization of Untrusted Data

Use other data storage and transmission formats, such JSON or XML, or only deserialize data from reliable sources.


  1. Use Secure Serialization Protocols

Use a serialisation format with built-in security features, such Google's Protocol Buffers or Apache Avro, which provides message authentication codes and encryption.


  1. Keep Software Up-to-Date

Patch any known vulnerabilities by updating the programme and its components on a regular basis.


SQL Injection Vulnerabilities

Web applications that connect to SQL databases are vulnerable to SQL injection issues. An attacker may exploit these flaws if they are able to insert malicious SQL code into the input fields of a web application. This code gives the attacker the ability to access the database without permission or to make unauthorised changes to the database.


Examples of SQL Injection Attacks:


Here are some examples of SQL injection attacks:


  1. Accessing Private Data

A SQL injection flaw might allow an attacker to access private data stored in a database. To steal users' credentials, an attacker may, for instance, insert SQL code into a login form.


  1. Changing or Erasing Information

Data in a database might be altered or deleted if an attacker exploited a SQL injection flaw. To remove or alter specific entries in a database, an attacker may, for instance, insert SQL code into a search form.


  1. Denial of Service (DoS)

A denial of service might be triggered by an attacker using a SQL injection flaw. To crash a database, an attacker may, for instance, insert SQL code into a search form.


Methods for Preventing SQL Injection Vulnerabilities


Here are some methods for preventing SQL injection vulnerabilities:


Query Parameters: Instead of using dynamic SQL statements, try using parameterized queries. This makes sure that the user's input is just data and not code.


Verifying Inputs: Make sure the input only includes the correct characters in the right order. As a result, attackers won't be able to insert harmful SQL code into your form fields.


Pre-Recorded Actions: Instead of using SQL statements, programmatically use a stored procedure to get data from the database. By reducing the privileges that programmes have to the database, SQL injection attacks may be avoided.


Restricting Access for Certain Users: Users' access to the database should be restricted to the bare minimum required for them to do their jobs. This may stop malicious actors from accessing sensitive information or making unauthorised changes to it.


Maintenance of Software: Keeping software up-to-date helps reduce the risk of SQL injection by addressing previously discovered security issues.


Cross-Site Scripting (XSS) Vulnerabilities


When a website fails to adequately verify or sanitise user input, it leaves itself open to Cross-Site Scripting (XSS) attacks, in which malicious code is injected into the website. In this way, each person who accesses the compromised website runs the risk of having their session hijacked, credentials stolen, or browser redirected to a phishing domain. Reflected XSS, Stored XSS, and DOM-based XSS are the three main forms of XSS assaults.


Examples of XSS Attacks


  1. Reflected XSS: 

The attacker baits the victim into clicking on a link by embedding malicious code in the URL. After the victim opens the link, the malware is downloaded and run on their browser, giving the attacker access to all of their private information. 


  1. Stored XSS

An attacker compromises a website by inserting malicious code into the site's database, where it remains unremovable. When a victim accesses the compromised website, their browser will run the malicious code, giving the hacker complete control over the victim's session. In this example, an adversary leaves a remark on a blog post that contains malicious JavaScript code. The attacker gains access to the target session when other users see the blog post and the code is run on their browsers.

  1. DOM-based XSS

A DOM injection attack is one in which malicious code is inserted into a web page and then executed by the victim's web browser. For instance, a susceptible web app may alter the page's content on the fly based on the value of the hash fragment in the URL. An adversary may compromise a user's system by inserting malicious JavaScript code within the hash fragment, which will be run by the user's browser upon page load.


Methods for Preventing XSS Vulnerabilities


  1. Verifying User Input

Validate and sanitise user input before using it in the programme.


  1. Encoding for Output

To prevent malicious code from being run, encode all user input before it is presented in the application's output.

  1. CSP (Content Security Policy)

Create a Content Security Policy to specify the acceptable content sources for the programme.


  1. Embrace Library and Framework Usage

Take use of XSS security features already present in libraries and frameworks like AngularJS, React, and Vue.js.


  1. Cookies and Safety

To stop hackers from stealing your session cookies, set the HttpOnly and Secure settings on your cookies.


  1. Upgrade and Fix

Provide security updates and patches on a regular basis to address any flaws in the software.



Cross-Site Request Forgery (CSRF) Vulnerabilities


Web security flaws like Cross-Site Request Forgery (CSRF) may be used by malicious actors to deceive users into doing undesired activities on a website. A user is vulnerable to this kind of attack if, while signed into the site, they browse a hacked page or click on a malicious link. The malicious code then makes a request to the website in the user's name, which might compromise their account or reveal private data.


Examples of CSRF Attacks


When an attacker sends a user a fake but legitimate-looking email with a link to a website, that's an example of a cross-site request forgery (CSRF) attack. When a user clicks on the link, malicious code is sent to the website, which then executes the action the user requested (such as transferring cash or changing their password).


A CSRF attack also occurs when an adversary constructs a website with a form that sends a request to an authorised server. An attacker may submit a form and make a request to a genuine website by tricking a user into visiting a link on the attacker's website.


Methods for Preventing CSRF Vulnerabilities


There are several methods for preventing CSRF vulnerabilities, including:


  1. Using a One-of-a-Kind Token

Every form submission on a website may contain a session token that was generated specifically for that user's session. The website will not proceed with the request until it has verified that the token is legitimate.


  1. Verifying the Request's Origin

The HTTP Referer header identifies the page from which the request was made, so websites may use it to verify the request's legitimacy.


  1. If You Use Cookies from the Same Site

Cookies that are only accessible from the originating site may help avoid CSRF attacks.


  1. Protecting Frameworks Against Cross-Site Request Forgery

Ruby on Rails and Django are only two examples of the many web frameworks that provide inbuilt CSRF security for their users.


  1. User Training

Users may be taught the significance of always logging out of their accounts and the dangers of visiting unfamiliar links.



Authentication and Authorization Vulnerabilities


Weaknesses in the procedures used to verify the identities of users and provide them access to restricted areas or data on a system or network are known as authentication and authorization vulnerabilities. When a user's identity cannot be verified by the system or when an attacker is able to circumvent the authentication procedure, we speak about an authentication vulnerability. When a user is given access to resources that they should not have access to, or when an attacker is able to raise their privileges to acquire access to resources that they should not have access to, we have an authorization vulnerability.


Examples of Authentication and Authorization Attacks


A brute-force attack is a kind of authentication assault in which an attacker tries to guess a user's password by attempting a large number of possible permutations. In a phishing assault, for instance, an attacker develops a website that seems identical to a real one in order to deceive consumers into giving up their login information.


Authorization attacks include privilege escalation, in which an attacker starts out with limited access to a system or network and subsequently exploits a flaw to obtain full control over it. To use yet another instance, a cross-site scripting (XSS) attack occurs when an adversary injects malicious code into a website, which is subsequently run in the context of other users, so giving the adversary access to the targets' private data.


Methods for Preventing Authentication and Authorization Vulnerabilities


There are several methods for preventing authentication and authorization vulnerabilities, including:


  1. Robust Techniques for Authenticating Users

To verify that users are who they say they are, use robust authentication systems like multi-factor authentication.


  1. Policy on Passwords

Insist on stringent password regulations, such as those that demand frequent password changes and the use of complicated passphrases.


  1. Confine Access

To ensure that users only have access to the features they need to do their tasks, use the concept of least privilege.


  1. Ongoing Inspections

In order to identify illegal access and privilege escalation, it is important to conduct regular audits of user accounts and access logs.


  1. Safe Programming Techniques

Make sure all user input is properly evaluated and sanitised and avoid security flaws like XSS attacks by following safe coding principles.


  1. Security Frameworks Must be Implemented

To guarantee the safety of user authentication and authorisation, it is recommended to employ a security framework like OAuth or OpenID Connect.





Java security is crucial in ensuring the confidentiality, integrity, and availability of critical information. In this post, we discussed the top 10 Java security vulnerabilities and how to avoid becoming a victim of them. Future developers should take a Java Developer course to learn the best practices for securing Java programmes and checking for vulnerabilities on a regular basis. Here, programmers may discover some best practices for protecting Java programmes. Developers may protect private information from prying eyes and reduce the likelihood of a security breach by following these tried-and-true standards.