As one of the most common network security threats, cross-site scripting (XSS) attacks are almost 75% of large companies As early as 2019. In addition, almost 40% of network attacks are carried out against XSS vulnerabilities.
Cross-site scripting has affected websites operated by web giants such as eBay, Google, Facebook, and Twitter. But cross-site scripting is not a new cyber threat. In fact, XSS attacks have existed almost since the birth of the Web.
To help you prevent XSS attacks, this guide focuses on everything you need to know about cross-site scripting. After reading this guide, you will have a better understanding of how cross-site scripting works and how to protect your WordPress site.
What is cross-site scripting (XSS)?
Cross-site scripting (XSS) refers to a type of network attack that injects malicious scripts into other trusted and trusted websites.
How does cross-site scripting work?
Cybercriminals can perform XSS attacks on WordPress sites in two ways. They can use user input or bypass the same-origin policy. Let’s take a look at these two methods to learn more about cross-site scripting.
Operate user input
The problem is that not all WordPress plugins and themes are 100% secure, and many of them do have XSS vulnerabilities. This means to you that cybercriminals can use WordPress vulnerabilities in input fields to run malicious activities.
Ideally, the site search bar (or any other user input field) should only accept plain text instead of commands as input. However, WordPress does have a user input vulnerability, through which hackers can enter execution code in the input field and send it to the database.
Bypass Same Origin Policy
The same origin policy restricts one page from retrieving information from other pages. According to this policy, web browsers only allow scripts contained in the first web page to access data in the second web page, provided they share the same source. This helps ensure that no cross-site requests are made.
The policy stipulates that if you open your Facebook page and online banking in the same browser, the two websites cannot share information with each other. However, if you have multiple Facebook tabs open (share the same source), they can exchange scripts and other data with each other.
Despite the same-origin policy and other security measures to prevent cross-site requests, cybercriminals have found a way to use session cookies to bypass the policy. This is effective because every time you open the browser, it will generate a session cookie to verify your identity as a website user and help you move smoothly from one page to another.
Session cookies store login credentials (including your WordPress site), credit card information, shipping details, and other sensitive data. This is how it works. Suppose you want to log in to your online banking account. When you open the website, a session cookie is generated. If it is not a session cookie, you must log in to your online banking account every time you want to switch pages.
It is not uncommon for users to have vulnerabilities in their browsers. If anything, cybercriminals will use the code they inject into the user to steal session cookies. In this way, hackers can steal cookies of all websites opened in the user’s browser. These cookies can then be used to log in to the user’s account to impersonate them and steal financial data.
Why is cross-site scripting dangerous?
When attackers find a way to exploit XSS vulnerabilities, they can steal account credentials, financial data and promote phishing scams. They can also spread computer worms or access users’ computers remotely. In addition, XSS attacks allow hackers to perform the following actions:
- Hijack user account
- Spread malware
- Remotely control the user’s computer
- Scan and use intranet applications
XSS attacks are generally considered less dangerous than SQL injection. However, when combined with social engineering, cross-site scripting allows cybercriminals to launch advanced and extremely dangerous attacks, including Trojan implantation, keylogging, phishing, identity theft, and cross-site request forgery.
In order to combat XSS attacks, large IT companies have launched a special bug bounty program. These procedures are implemented by many organizations and provide compensation or recognition to users who report XSS vulnerabilities in scripts. In this way, companies invest in network security by letting other developers identify their mistakes.Google even launched game You can practice dispatching XSS errors here.
Types of XSS attacks
Cross-site scripting attacks are mainly divided into three types: reflection type, storage type and DOM-based XSS. To better understand how XSS works, let’s take a look at each type of XSS vulnerability.
Store cross-site scripting
Stored XSS vulnerabilities (aka Persistent or Type I) can occur when user input is stored in a database, comment field, visitor log, or other target server. The victim can then retrieve the stored data from the web application (the data presented in the browser is not yet secure). In this way, when a hacker conducts an attack, the browser’s XSS filter cannot see the payload, and if the victim visits the affected page, the payload may be accidentally triggered.
Reflective cross-site scripting
When a web application immediately returns user input in search results, error messages, or any other response, a reflective XSS vulnerability (aka non-persistent or type II) occurs. In this case, the data entered by the user is reflected and not stored, allowing hackers to inject malicious XSS scripts. Unlike stored XSS, reflective XSS targets the website itself rather than website visitors.
TA DOM-based XSS vulnerabilities (aka Type 0) occur in the DOM (Document Object Model) instead of the HTML part. The source of reading malicious code can be a URL or a specific element of HTML.
How to prevent cross-site scripting attacks?
Now that you have understood the basics of XSS, let’s take a look at proven methods to prevent XSS attacks.
There are multiple ways to protect your WordPress site from XSS attacks. If you have advanced technical expertise, you can add code snippets to validate and sanitize user input. However, if you are not familiar with the technical part of WordPress, it is best to delegate the work to your technical team or hire a professional who can take these measures for you.
At the same time, you can do two things to prevent cross-site scripting attacks.
Install security plugin
Installing a secure WordPress plugin is the first step in achieving the ultimate security of your WordPress website. When choosing a security plug-in, please use this checklist as a reference to ensure that the plug-in has the functions required to protect the site’s security.
- The plugin will periodically scan your website for malware.
- The plugin uses a firewall to block any seemingly malicious traffic.
- The plugin can implement WordPress enhancements.
- The plugin allows you to manage all WordPress updates.
- A plugin backs up your WordPress site, so in case of an attack, you can restore your site.
Install dedicated plug-ins
Installing anti-XSS plugins is another way to prevent cross-site scripting. The Anti-XSS plug-in works by blocking parameters commonly used in cross-site scripting attacks. For example, these plugins can protect user input fields, such as your website’s comment form, login field, or search bar.
The bottom line– 39% of WordPress vulnerabilities Related to cross-site scripting issues. The company lost millions of dollars while fighting the consequences of cross-site scripting attacks. In order to avoid XSS attacks against your website, it is important to understand what cross-site scripting is and take preventive measures.
To protect your website from cross-site scripting attacks, you should verify and clean up your input fields. In addition, you can install security and dedicated anti-XSS plugins to help you keep your WordPress site safe.