In the ever-evolving world of cybersecurity, vulnerabilities in widely-used libraries and frameworks often present the most significant risks. One such vulnerability that has recently garnered attention is the cross-site scripting (XSS) flaw in the popular jQuery JavaScript library, identified as CVE-2020-11023. The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has added this flaw to its Known Exploited Vulnerabilities (KEV) catalog, signaling a serious concern for web developers and organizations that have failed to update their systems.
In this blog, we’ll explore what this vulnerability is, why it’s still a threat today, and what steps developers and organizations should take to mitigate the risks. Along the way, we’ll discuss the importance of keeping third-party dependencies up to date and offer practical tips for preventing such vulnerabilities from creeping into your own web applications.
What is the jQuery XSS Vulnerability?
At its core, CVE-2020-11023 is a cross-site scripting (XSS) vulnerability that affects jQuery versions prior to 3.5.0. XSS vulnerabilities allow attackers to inject malicious scripts into web pages viewed by unsuspecting users. In the case of jQuery, the flaw specifically arises from how the library handles <option>
elements in HTML forms. When the user input is improperly handled, it can be exploited to execute arbitrary JavaScript code in the context of the user’s browser.
This flaw was originally identified in 2020, and while it was promptly patched in the jQuery 3.5.0 release, many websites and web applications continue to use older, vulnerable versions of jQuery. This outdated code provides an ideal attack vector for cybercriminals looking to target high-traffic websites.
For further details on the jQuery XSS vulnerability and its impact, you can explore the official CISA advisory and GitHub advisory.
How Does the Flaw Work?
The vulnerability occurs when jQuery fails to properly sanitize user input inside an HTML <option>
tag. This issue allows attackers to inject malicious scripts into the options of a select dropdown or other form elements that use option
tags. These scripts, once injected, can be executed within the victim’s browser when they interact with the compromised page.
What makes this vulnerability particularly dangerous is that it allows for the execution of arbitrary JavaScript. This could enable attackers to steal sensitive data like login credentials, session tokens, or other personal information. Attackers can also carry out other malicious activities such as redirecting users to phishing sites or using the compromised session to gain unauthorized access to accounts.
Why Is This a Big Deal?
While it might seem like a minor issue, this vulnerability poses a significant risk because of how widely jQuery is used in modern web development. jQuery is a go-to JavaScript library for simplifying tasks like DOM manipulation, event handling, and AJAX requests. It has been used for years by millions of websites and web applications around the world.
As of today, jQuery is still a cornerstone of web development despite the rise of newer, more modern JavaScript frameworks. Many businesses, both large and small, continue to use jQuery due to its ease of use and compatibility with a wide range of browsers. This means that even though the vulnerability has been patched for nearly five years, countless websites may still be at risk because they are running outdated versions of the library.
The CISA Announcement
CISA’s decision to add CVE-2020-11023 to its Known Exploited Vulnerabilities (KEV) catalog is a clear sign that this vulnerability is still being actively exploited. The KEV catalog is designed to help organizations prioritize the remediation of vulnerabilities that are being actively exploited in the wild. By adding this flaw to the list, CISA is effectively warning web developers and administrators that this is a critical issue that should be addressed immediately.
The Persistent Threat of Outdated Libraries
One of the key takeaways from this incident is the ongoing risk of outdated third-party libraries. While patching known vulnerabilities is a common practice in the world of cybersecurity, many developers and organizations struggle to keep their dependencies up to date. In some cases, upgrading to a newer version of a library can break existing functionality, leading to compatibility issues that make the upgrade process daunting.
However, the risk of leaving outdated libraries in place far outweighs the inconvenience of updating them. Cybercriminals are constantly on the lookout for such vulnerabilities, knowing that many organizations are slow to patch their systems. This creates a dangerous gap that attackers can exploit for months or even years after a patch has been released.
How to Mitigate the Risk
If you’re a web developer or an organization relying on jQuery for your web applications, it’s critical to address this vulnerability as soon as possible. Here are some steps you can take to mitigate the risk:
1. Upgrade to jQuery 3.5.0 or Later
The first and most important step is to upgrade your jQuery version to 3.5.0 or later. This version of jQuery was specifically released to address the CVE-2020-11023 vulnerability, so upgrading will immediately close this security gap. Make sure to thoroughly test your application after the upgrade to ensure that everything functions as expected.
2. Audit Your Dependencies Regularly
Keeping your third-party libraries up to date is crucial to maintaining a secure web application. Use automated tools to regularly audit your dependencies and ensure that all libraries are up to date. Tools like Snyk, npm audit, and OWASP Dependency-Check can help identify outdated or vulnerable libraries within your application.
By staying on top of these audits, you can address vulnerabilities before they become serious threats. It’s also important to check for updates not just to jQuery, but to all of the libraries and frameworks you use in your project.
3. Implement Secure Coding Practices
In addition to keeping libraries updated, it’s essential to implement secure coding practices in your web application. For example, always sanitize and validate user input, especially when it is used in rendering HTML or interacting with JavaScript. By ensuring that user input is properly escaped, you can prevent malicious code from being injected into your pages.
One of the best ways to avoid XSS vulnerabilities is to use a security-focused content management system (CMS) or framework that automatically handles input sanitization. For example, many modern web development frameworks, like Angular and React, come with built-in protections against XSS attacks.
4. Stay Informed About Security Advisories
Cybersecurity is an ever-evolving field, and new vulnerabilities are discovered regularly. It’s crucial to stay informed about security advisories and threat reports from trusted sources like CISA, the National Vulnerability Database (NVD), and major cybersecurity blogs. This will help you stay ahead of emerging threats and apply necessary patches before your systems are targeted.
Why You Should Care About jQuery’s Vulnerability
Web developers and security professionals should take this vulnerability seriously, as it represents a broader trend in the security landscape. Even older and widely-used technologies can pose a significant risk if they aren’t maintained and updated properly. The ongoing exploitation of the CVE-2020-11023 vulnerability shows that even the most well-known and trusted libraries can be a target for attackers if left unchecked.
Moreover, organizations that ignore security updates for years are more likely to experience data breaches, which can lead to reputational damage, loss of customers, and financial penalties. WebOrion, as a leader in cybersecurity, understands the critical importance of staying proactive about these threats, and we encourage our clients to adopt a similar approach.
Final Thoughts: Take Action Now
The addition of CVE-2020-11023 to CISA’s Known Exploited Vulnerabilities catalog is a stark reminder of the importance of keeping third-party libraries up to date and following best practices for secure coding. By upgrading your jQuery version, auditing your dependencies, and implementing proper security controls, you can protect your web applications from this threat and prevent similar issues in the future.
As always, cybersecurity is about being proactive rather than reactive. Staying informed, adopting security best practices, and promptly addressing vulnerabilities will help you stay one step ahead of cybercriminals.
For more information or assistance with securing your web applications, feel free to contact us.