How to fix cross-site scripting persistent in Java?

Before we jump to cross-site scripting or XSS it is vital to understand a core security feature called Same Origin Policy (SOP) so that we are on the same page. SOP is a policy that stops one website from reading or writing data. The policy essentially checks for three different things in the origin- Protocol, Host, Port. If all the three are the same for two different origins then the browser allows cross-origin read or write. This is a great feature ensuring some basic web security.

But what if we had control over the Javascript of another website? We know that Javascript has access to HTML documents that are provided by the browser. This means one can manipulate the DOM and deface the webpage. Hence, having access to Javascript on another website in a different user’s context can be very problematic. But now the question is can we inject some Javascript into another website? Yes, we can and that’s exactly what Cross-Site Scripting or XSS does. 

What is Cross-Site Scripting?

Cross-Site Scripting is nothing but a Javascript injection technique. In this, attackers aim to carry out any actions that the user can perform and also, access the user’s data. If by any chance, the victim possesses premium access, then attackers might be able to control the application’s functionality and data. 

There are two types of Cross-Site Scripting attacks namely- 

• Nonpersistent or Reflected XSS. 
• Persistent or Stored XSS. 

What is Persistent Cross-Site Scripting?

Persistent Cross-Site Scripting comes to the fore when an application receives data from an untrusted source and that data is included within its later HTTP responses in an unsafe way. There are multiple sources of untrusted data. They can arrive via HTTP requests. For instance, user nicknames in a chat room, comments on a post, or contact details on an order. In other cases, data can come from a marketing operation displaying social media posts.

In Persistent Cross-Site Scripting, attackers do not need to find external ways for exploiting. Rather, they place their exploit into the application itself and wait for the users to confront it. However, this scripting method is only relevant in situations where cross-site scripting vulnerability affects users who are currently logged in to the application.  

How to Fix Cross-Site Scripting Persistent in Java?

The most straightforward approach to avoid cross-site scripting persistent vulnerabilities is to sanitize user data and safely handle inputs. However, this might take a considerable time for the software developers. One of the least time-consuming solutions is Web Application Firewalls (WAF).  

WAFs are used to detect and fix XSS attacks in real-time. They analyze traffic metrics such as sessions, packet size, and various patterns. After doing a thorough analysis, they decide whether to block or allow the traffic. However, they are not completely efficient in doing its task. They are incapable of providing all attack signatures in your database. No doubt WAFs provide great attack detection for applications and they are one of the essential methods of boosting security. But WAFs are not enough when used alone. 

To better fix XSS persistent attacks in Java, one needs to go beyond WAFs. This is exactly where Sqreen comes in. Sqreen is a cloud-based security product aimed to protect one’s application directly. It allows one to view its application more clearly. This makes developers stay ahead in the game as in cybersecurity, visibility means leveling up of development game. Sqreen can also be used to run the most popular XSS persistent checks in Java. This can be further used for deciding what to do with malicious detection. It provides multilayered protection for one’s application and is quite efficient in examining application behavior to prevent real-time exploits.