CVE-2020-11023 JQuery Cross-Site Scripting (XSS)

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CVE-2020-11023: Cross-Site Scripting (XSS) Vulnerability in jQuery

CVE-2020-11023 is a cross-site scripting (XSS) vulnerability identified in jQuery versions greater than or equal to 1.0.3 and before 3.5.0. This vulnerability allows attackers to execute untrusted code by passing HTML containing <option> elements from untrusted sources to jQuery’s DOM manipulation methods, such as .html() and .append(). Even after sanitizing the input, the vulnerability can be exploited. The issue was addressed in jQuery version 3.5.0.

What is Vulnerable to CVE-2020-11023

All jQuery versions from 1.0.3 up to, but not including, 3.5.0 are affected by this vulnerability. Web applications utilizing these versions are at risk, especially if they process HTML content from untrusted sources. Notably, Oracle Application Express (APEX) versions prior to 20.2 include vulnerable jQuery versions, making them susceptible to this issue.

Mitigation and Remediation for CVE-2020-11023

To mitigate this vulnerability:

  1. Update jQuery: Upgrade to jQuery version 3.5.0 or later, where the issue has been resolved.

  2. Sanitize Inputs: Ensure that all HTML content from untrusted sources is properly sanitized before being processed by jQuery’s DOM manipulation methods.

  3. Implement Content Security Policy (CSP): Deploy CSP headers to restrict the execution of untrusted scripts and reduce the risk of XSS attacks.

  4. Review Dependencies: Audit all web applications and libraries to identify and update any that include vulnerable jQuery versions.

Impact of Successful Exploitation of CVE-2020-11023

Exploiting this vulnerability allows attackers to inject and execute malicious scripts within the context of the affected web page. This can lead to:

  • Data Theft: Unauthorized access to sensitive information, such as user credentials and personal data.

  • Session Hijacking: Taking over user sessions to impersonate legitimate users.

  • Defacement: Altering the appearance and content of web pages.

  • Malware Distribution: Injecting malicious code to distribute malware to users.

The severity of this vulnerability is underscored by its widespread impact on numerous web applications relying on jQuery.

Proof of Concept for CVE-2020-11023

A proof-of-concept (PoC) exploit demonstrates that by injecting a specially crafted <img> tag with an onerror event handler into an HTML string processed by jQuery’s .html() method, an attacker can execute arbitrary JavaScript code. For example:

<style><style /><img src=x onerror=alert(1)>
 

This PoC highlights the ease with which the vulnerability can be exploited, emphasizing the need for prompt remediation.

 

CVE-2020-11023 is a significant XSS vulnerability affecting multiple versions of jQuery. Immediate action, including updating to the latest version and implementing robust input sanitization, is essential to protect web applications from potential exploitation. Organizations should also review their use of jQuery in all projects to ensure comprehensive mitigation.


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