WordPress Plugin Vulnerability Report – Modern Events Calendar Lite – Authenticated (Admin+) Stored Cross-Site Scripting – CVE-2023-4021

Q: What is the nature of the vulnerability in the Modern Events Calendar Lite plugin?

What is the nature of the vulnerability in the Modern Events Calendar Lite plugin? The vulnerability in the Modern Events Calendar Lite plugin for WordPress pertains to Stored Cross-Site Scripting (or XSS). Specifically, it's present in versions up to, but not including, 7.1.0. This vulnerability arises from inadequate input sanitization and output escaping, especially concerning the Google API key and Calendar ID. As a result, attackers who have administrator-level permissions can inject arbitrary web scripts into pages. These scripts will then execute whenever a user visits the compromised page. Notably, this vulnerability impacts multi-site WordPress installations and those installations where the unfiltered_html feature has been turned off.

Q: How can users protect their WordPress sites from this vulnerability?

How can users protect their WordPress sites from this vulnerability? To safeguard your WordPress site from this vulnerability, it's essential to immediately update the Modern Events Calendar Lite plugin to version 7.1.0 or a higher version. This updated version has patched the vulnerability. Users should also review their website to detect any unauthorized JavaScript or HTML codes that might have been added. For those seeking alternative plugins, they might consider switching to other calendar plugins like The Events Calendar. Above all, one crucial piece of advice is to consistently update plugins since updated versions often contain patches for identified vulnerabilities.

Q: Has this vulnerability been fixed, and if so, in which version?

Has this vulnerability been fixed, and if so, in which version? Yes, the vulnerability in the Modern Events Calendar Lite plugin has been addressed. The issue has been patched in version 7.1.0 of the plugin. It's vital for users to ensure they're using this version or a more recent one to protect their sites from potential exploitation stemming from this vulnerability.

Q: Who discovered the vulnerability in the Modern Events Calendar Lite plugin?

Who discovered the vulnerability in the Modern Events Calendar Lite plugin? The vulnerability in the Modern Events Calendar Lite plugin for WordPress was identified and reported by a researcher named Marco Wotschka. Researchers like Marco play a vital role in the digital landscape by spotting potential security risks in software and alerting both the developers and the broader community to take corrective measures.

Q: What is the potential impact of this Stored Cross-Site Scripting (XSS) vulnerability?

What is the potential impact of this Stored Cross-Site Scripting (XSS) vulnerability? Stored Cross-Site Scripting (XSS) vulnerabilities, such as the one found in the Modern Events Calendar Lite plugin, can have severe consequences. An attacker exploiting this vulnerability can inject malicious scripts into web pages. When unsuspecting users access these compromised pages, the malicious scripts execute. These scripts can lead to phishing attacks, cookie theft, and in some extreme cases, a complete takeover of the website. Such vulnerabilities pose risks to both website administrators and visitors, emphasizing the importance of timely patches and updates.

Q: Is this the first time that a vulnerability has been found in the Modern Events Calendar Lite plugin?

Is this the first time that a vulnerability has been found in the Modern Events Calendar Lite plugin? No, this isn't the first instance of a vulnerability being detected in the Modern Events Calendar Lite plugin. In 2021, a reflected XSS issue was identified and subsequently addressed in version 5.14.5 of the plugin. It's a reminder that software, including plugins, can have vulnerabilities that surface over time, underscoring the necessity of regular updates and active security monitoring.

Q: Why was the Modern Events Calendar Lite plugin removed from the WordPress repository?

Why was the Modern Events Calendar Lite plugin removed from the WordPress repository? The Modern Events Calendar Lite plugin was temporarily removed from the WordPress repository to verify the fix for the identified vulnerability. Such actions are commonly taken as a precautionary measure to prevent more users from downloading potentially vulnerable versions of a plugin, and to give developers time to confirm that the issues have been fully resolved.

Q: What is the significance of the CVSS score mentioned in the details?

What is the significance of the CVSS score mentioned in the details? The CVSS, or Common Vulnerability Scoring System, is a standardized method used to assess and communicate the severity of vulnerabilities. The score for this vulnerability in the Modern Events Calendar Lite plugin is 4.4, which falls under the "medium" category. This suggests that while the vulnerability presents a definite risk, it's not the most severe type of vulnerability one could encounter. However, even medium-severity vulnerabilities should be addressed promptly to maintain website security.

Q: How does this vulnerability specifically affect multi-site installations?

How does this vulnerability specifically affect multi-site installations? This vulnerability particularly impacts multi-site installations of WordPress and sites where the unfiltered_html capability has been disabled. Multi-site installations allow multiple virtual sites to share a single WordPress installation. In these setups, if one site gets compromised, there's a potential risk for other sites within the same network. This can lead to a broader scale of damage or unauthorized access across multiple sites, emphasizing the need for immediate corrective action.

Q: How can website owners stay informed about vulnerabilities in plugins they use?

How can website owners stay informed about vulnerabilities in plugins they use? To remain updated on vulnerabilities in plugins, website owners should consider using WordPress security plugins like Wordfence. Such plugins can automatically alert users to outdated software and potential vulnerabilities. Additionally, subscribing to security bulletins, following the updates from plugin developers, and regularly visiting the official WordPress plugin repository can also help in staying informed. It's essential to prioritize timely updates, especially for widely-used plugins, to reduce the risk of potential breaches.

By Your WP Guy | September 29, 2023

Plugin Name: Modern Events Calendar Lite

Key Information:

Software Type: Plugin
Software Slug: modern-events-calendar-lite
Software Status: Removed
Software Author: webnus/
Software Downloads: 3,047,787
Active Installs: 100,000
Last Updated: September 28, 2023
Patched Versions: 7.1.0
Affected Versions: <7.1.0

Vulnerability Details:

Name: Modern Events Calendar lite < 7.1.0 - Authenticated (Admin+) Stored Cross-Site Scripting
Type: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE: CVE-2023-4021
CVSS Score: 4.4 (medium)
Publicly Published: September 28, 2023
Researcher: Marco Wotschka

Description:

The Modern Events Calendar lite plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Google API key and Calendar ID in versions up to, but not including, 7.1.0 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with administrator-level permissions and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This only affects multi-site installations and installations where unfiltered_html has been disabled.
Summary:

The Modern Events Calendar Lite plugin for WordPress has a vulnerability in versions up to and including <7.1.0 that allows for Authenticated (Admin+) Stored Cross-Site Scripting. This vulnerability has been patched in version 7.1.0.

Detailed Overview:

The Modern Events Calendar Lite plugin up to version 7.1.0 has an input validation issue that allows authenticated users with admin access to inject arbitrary JavaScript code into pages via the Google API key and Calendar ID fields. This stored cross-site scripting vulnerability can be exploited to execute malicious scripts when a user views a compromised page. The vulnerability was reported by researcher Marco Wotschka and has been addressed in Modern Events Calendar Lite version 7.1.0 through improved input sanitization. This issue poses a risk of malicious code execution and affects multi-site installations and sites where the unfiltered_html capability has been disabled.

Advice for Users:

Immediate Action: Update to Modern Events Calendar Lite version 7.1.0 or higher as soon as possible.
Check for Signs of Vulnerability: Review your site for unauthorized added JavaScript or HTML code.
Alternate Plugins: Consider using alternate calendar plugins like The Events Calendar as a precaution.
Stay Updated: Always keep your plugins updated to avoid potential vulnerabilities.
Conclusion:

This vulnerability demonstrates the importance of timely security updates for WordPress plugins. Users should upgrade to the latest Modern Events Calendar Lite 7.1.0 release that contains the fix for this issue.

References:

https://www.wordfence.com/threat-intel/vulnerabilities/wordpress-plugins/modern-events-calendar-lite

https://www.wordfence.com/threat-intel/vulnerabilities/wordpress-plugins/modern-events-calendar-lite/modern-events-calendar-lite-710-authenticated-admin-stored-cross-site-scripting

Detailed Report:

Keeping your WordPress website and its plugins up-to-date is critical for security. Unfortunately, outdated plugins can harbor dangerous vulnerabilities that put your site at risk of compromise. One such vulnerable plugin is Modern Events Calendar Lite versions prior to 7.1.0. This popular calendar plugin contains an authenticated stored cross-site scripting vulnerability that could allow malicious scripts to be injected into your site. While the vulnerability has been patched, any site still running an old version of Modern Events Calendar Lite could be exploited. In this post, we’ll break down this recently disclosed vulnerability, assess the risks it poses, and provide actionable advice to help ensure your WordPress site stays secure.

Modern Events Calendar Lite is a free events calendar plugin with over 3 million downloads. It allows you to create and manage events on your WordPress site. However, versions before 7.1.0 contain a stored cross-site scripting (XSS) vulnerability. This issue allows authenticated users with admin access to inject arbitrary JavaScript code into pages via the Google API key and Calendar ID fields. An attacker could exploit this to execute malicious scripts when a user views a compromised page.

This is a serious vulnerability that poses risks of phishing, cookie theft, and full site takeover if exploited. The vulnerability received a CVSS severity score of 4.4 (medium). It affects multi-site installations and sites where unfiltered_html capabilities are restricted.

The good news is that Modern Events Calendar Lite patched this vulnerability in version 7.1.0, released on September 28, 2023. At the time of writing, the plugin has been temporarily removed from the WordPress repository pending verification of the fix.

To protect your site, it is strongly recommended to update to the latest secure version 7.1.0 or higher immediately once it is reinstated. Be sure to delete any existing vulnerable versions. If you cannot update immediately, consider removing the plugin or restricting admin access as a temporary precaution.

This is not the first vulnerability found in Modern Events Calendar Lite. In 2021, a reflected XSS issue was addressed in version 5.14.5. Regularly updating plugins is key to getting timely security fixes.

As a busy small business owner, staying on top of plugin vulnerabilities may not be feasible. Consider having your web developer or agency monitor and manage updates for you. WordPress security plugins like Wordfence can also automatically alert you to outdated software. Prioritizing updates of popular plugins like calendars is wise to avoid becoming an easy target.

Keeping WordPress and its plugins updated is an essential website security practice. The Modern Events Calendar Lite vulnerability illustrates that threats emerge frequently. Taking proactive steps to lock down your site will reduce the chances of a serious breach that could interrupt your business.

Don't tackle WordPress security alone - the consequences of a breach are too great. At Your WP Guy, our managed WordPress maintenance services include layers of protection like auto-updates, malware scanning, firewalls and 24/7 monitoring by WordPress experts. We become your outsourced IT team.

Let's chat about migrating your site to our managed hosting so you can finally stop worrying about security issues. We'll fully audit and lock down your site as part of onboarding. Call us at 678-995-5169 to keep your business safe online.

WordPress Plugin Vulnerability Report – Modern Events Calendar Lite – Authenticated (Admin+) Stored Cross-Site Scripting – CVE-2023-4021 FAQs

What is the nature of the vulnerability in the Modern Events Calendar Lite plugin?

The vulnerability in the Modern Events Calendar Lite plugin for WordPress pertains to Stored Cross-Site Scripting (or XSS). Specifically, it's present in versions up to, but not including, 7.1.0. This vulnerability arises from inadequate input sanitization and output escaping, especially concerning the Google API key and Calendar ID. As a result, attackers who have administrator-level permissions can inject arbitrary web scripts into pages. These scripts will then execute whenever a user visits the compromised page. Notably, this vulnerability impacts multi-site WordPress installations and those installations where the unfiltered_html feature has been turned off.

How can users protect their WordPress sites from this vulnerability?

To safeguard your WordPress site from this vulnerability, it's essential to immediately update the Modern Events Calendar Lite plugin to version 7.1.0 or a higher version. This updated version has patched the vulnerability. Users should also review their website to detect any unauthorized JavaScript or HTML codes that might have been added. For those seeking alternative plugins, they might consider switching to other calendar plugins like The Events Calendar. Above all, one crucial piece of advice is to consistently update plugins since updated versions often contain patches for identified vulnerabilities.

Has this vulnerability been fixed, and if so, in which version?

Who discovered the vulnerability in the Modern Events Calendar Lite plugin?

The vulnerability in the Modern Events Calendar Lite plugin for WordPress was identified and reported by a researcher named Marco Wotschka. Researchers like Marco play a vital role in the digital landscape by spotting potential security risks in software and alerting both the developers and the broader community to take corrective measures.

What is the potential impact of this Stored Cross-Site Scripting (XSS) vulnerability?

Stored Cross-Site Scripting (XSS) vulnerabilities, such as the one found in the Modern Events Calendar Lite plugin, can have severe consequences. An attacker exploiting this vulnerability can inject malicious scripts into web pages. When unsuspecting users access these compromised pages, the malicious scripts execute. These scripts can lead to phishing attacks, cookie theft, and in some extreme cases, a complete takeover of the website. Such vulnerabilities pose risks to both website administrators and visitors, emphasizing the importance of timely patches and updates.

Is this the first time that a vulnerability has been found in the Modern Events Calendar Lite plugin?

No, this isn't the first instance of a vulnerability being detected in the Modern Events Calendar Lite plugin. In 2021, a reflected XSS issue was identified and subsequently addressed in version 5.14.5 of the plugin. It's a reminder that software, including plugins, can have vulnerabilities that surface over time, underscoring the necessity of regular updates and active security monitoring.

Why was the Modern Events Calendar Lite plugin removed from the WordPress repository?

The Modern Events Calendar Lite plugin was temporarily removed from the WordPress repository to verify the fix for the identified vulnerability. Such actions are commonly taken as a precautionary measure to prevent more users from downloading potentially vulnerable versions of a plugin, and to give developers time to confirm that the issues have been fully resolved.

What is the significance of the CVSS score mentioned in the details?

The CVSS, or Common Vulnerability Scoring System, is a standardized method used to assess and communicate the severity of vulnerabilities. The score for this vulnerability in the Modern Events Calendar Lite plugin is 4.4, which falls under the "medium" category. This suggests that while the vulnerability presents a definite risk, it's not the most severe type of vulnerability one could encounter. However, even medium-severity vulnerabilities should be addressed promptly to maintain website security.

How does this vulnerability specifically affect multi-site installations?

This vulnerability particularly impacts multi-site installations of WordPress and sites where the unfiltered_html capability has been disabled. Multi-site installations allow multiple virtual sites to share a single WordPress installation. In these setups, if one site gets compromised, there's a potential risk for other sites within the same network. This can lead to a broader scale of damage or unauthorized access across multiple sites, emphasizing the need for immediate corrective action.

How can website owners stay informed about vulnerabilities in plugins they use?

To remain updated on vulnerabilities in plugins, website owners should consider using WordPress security plugins like Wordfence. Such plugins can automatically alert users to outdated software and potential vulnerabilities. Additionally, subscribing to security bulletins, following the updates from plugin developers, and regularly visiting the official WordPress plugin repository can also help in staying informed. It's essential to prioritize timely updates, especially for widely-used plugins, to reduce the risk of potential breaches.

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Posted in Security, Vulnerabilities and tagged Admin-level security threat, Authenticated Stored XSS, Cross-Site Scripting (XSS), CVE-2023-4021, Cybersecurity advice, Input Sanitization, Marco Wotschka, Modern Events Calendar Lite, Multi-site vulnerability, Plugin Update, Plugin Vulnerability, Security Updates, Software patch, Web Development, Web safety, Website Protection, WordPress maintenance services., WordPress plugin risk, wordpress security, WordPress site management

WordPress Plugin Vulnerability Report – Modern Events Calendar Lite – Authenticated (Admin+) Stored Cross-Site Scripting – CVE-2023-4021

Plugin Name: Modern Events Calendar Lite

Key Information:

Vulnerability Details:

Description:

Detailed Overview:

Advice for Users:

References:

Detailed Report:

WordPress Plugin Vulnerability Report – Modern Events Calendar Lite – Authenticated (Admin+) Stored Cross-Site Scripting – CVE-2023-4021 FAQs

What is the nature of the vulnerability in the Modern Events Calendar Lite plugin?

What is the nature of the vulnerability in the Modern Events Calendar Lite plugin?

How can users protect their WordPress sites from this vulnerability?

How can users protect their WordPress sites from this vulnerability?

Has this vulnerability been fixed, and if so, in which version?

Has this vulnerability been fixed, and if so, in which version?

Who discovered the vulnerability in the Modern Events Calendar Lite plugin?

Who discovered the vulnerability in the Modern Events Calendar Lite plugin?

What is the potential impact of this Stored Cross-Site Scripting (XSS) vulnerability?

What is the potential impact of this Stored Cross-Site Scripting (XSS) vulnerability?

Is this the first time that a vulnerability has been found in the Modern Events Calendar Lite plugin?

Is this the first time that a vulnerability has been found in the Modern Events Calendar Lite plugin?

Why was the Modern Events Calendar Lite plugin removed from the WordPress repository?

Why was the Modern Events Calendar Lite plugin removed from the WordPress repository?

What is the significance of the CVSS score mentioned in the details?

What is the significance of the CVSS score mentioned in the details?

How does this vulnerability specifically affect multi-site installations?

How does this vulnerability specifically affect multi-site installations?

How can website owners stay informed about vulnerabilities in plugins they use?

How can website owners stay informed about vulnerabilities in plugins they use?

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