Vladimir Kolesnikov

Like any other software WordPress does have bugs and security vulnerabilities. They get fixed when the developers become aware of them. 
However, sometimes several WordPress releases are vulnerable. The problem is that the developers do not backport security updates to older WordPress releases. 
As a result, those who do not want to upgrade their WordPress installations (for example, because newer WP releases tend to consume more system resources and 
upgrade may result in having to use more expensive hosting) remain vulnerable.
ICS Security Fixes is the plugin for those who do not upgrade their WordPress: the plugin tries to fix known WordPress vulnerabilities 
at that remaining compatible with as many old WordPress releases as possible. 
And though it cannot fix all known vulnerabilities, it makes older WordPress installations more secure.
<h3>Warning</h3>
This plugins requires that PHP 5 be installed. PHP 4 is not supported.

ICS Security Fixes

The plugin tries to fix known WordPress vulnerabilities for older WordPress versions. Warning: For PHP 5 only.

Sami Ahmed Siddiqui

This plugin helps safeguard your website against two common types of Cross-Site Scripting (XSS) vulnerabilities:
<ul>
<li>Reflected XSS: This happens when harmful scripts are hidden in a website’s URL. If a user clicks a link with such a script, it can run in their browser, potentially stealing their data or taking control of their system.</li>
<li>Self-XSS: This occurs when a user’s own input on your website is displayed back to them in an unsafe way, allowing malicious scripts to run in their browser.</li>
</ul>
This plugin provides several layers of protection:
Blocking: When active, the plugin checks URLs for specific characters. If it finds any of these characters in the URL, it redirects the user to prevent a potential XSS attack. You can customize which characters to block or allow.
<ul>
<li>Opening Round Bracket <code>(</code></li>
<li>Closing Round Bracket <code>)</code></li>
<li>Less than Sign <code><</code></li>
<li>Greater than Sign <code>></code></li>
<li>Opening Square Bracket <code>[</code></li>
<li>Closing Square Bracket <code>]</code></li>
<li>Opening Curly Bracket <code>{</code></li>
<li>Pipe or Vertical Bar <code>|</code></li>
<li>Closing Curly Bracket <code>}</code></li>
</ul>
Encoding: For an extra layer of security, the plugin encodes certain characters found in URL parameters. This stops harmful code from running, even if it’s present in the URL. You can also choose to exclude specific parameters from being encoded.
<ul>
<li>Exclamation Mark <code>!</code></li>
<li>Double Quotation <code>"</code></li>
<li>Single Quotation <code>'</code></li>
<li>Opening Round Bracket <code>(</code></li>
<li>Closing Round Bracket <code>)</code></li>
<li>Asterisk Sign <code>*</code></li>
<li>Less than Sign <code><</code></li>
<li>Greater than Sign <code>></code></li>
<li>Grave Accent “`</li>
<li>Cap Sign <code>^</code></li>
<li>Opening Square Bracket <code>[</code></li>
<li>Closing Square Bracket <code>]</code></li>
<li>Opening Curly Bracket <code>{</code></li>
<li>Pipe or Vertical Bar <code>|</code></li>
<li>Closing Curly Bracket <code>}</code></li>
</ul>
Escaping HTML in <code>$_GET</code>: This plugin automatically makes HTML characters safe within the <code>$_GET</code> variable. This is vital if your website pulls data from URLs and displays it as part of your web page. It helps prevent malicious scripts from being injected through user-provided input.
<h3>Important Notes:</h3>
<ul>
<li>After activating the plugin, thoroughly test your website forms, especially if you use WooCommerce. Make sure the plugin doesn’t interfere with your shopping cart and checkout processes.</li>
<li>We welcome bug reports for this plugin on GitHub: <a href="https://github.com/samiahmedsiddiqui/prevent-xss-vulnerability/issues" rel="nofollow ugc">https://github.com/samiahmedsiddiqui/prevent-xss-vulnerability/issues</a>. Please remember that GitHub is for bug reports only, not general support.</li>
</ul>
By using this plugin and following these recommendations, you can significantly improve your website’s defense against XSS attacks.

Prevent XSS Vulnerability

Very useful plugin.

This WP plugin blocks XSS by encoding harmful URL characters & safely handling HTML in $_GET. Customizable settings for enhanced website security.

ICS Security Fixes vs Prevent XSS Vulnerability