WordPress Plugin Vulnerability Report – Simple Calendar – Cross-Site Request Forgery

Q: What is the Simple Calendar plugin?

What is the Simple Calendar plugin? The Simple Calendar plugin is a popular calendar plugin for WordPress sites. It allows you to easily display Google Calendar events on your WordPress site. With over 2.5 million downloads, it is a widely used plugin.

Q: What is the vulnerability in Simple Calendar?

What is the vulnerability in Simple Calendar? Versions prior to 3.2.5 of the Simple Calendar plugin contain a cross-site request forgery (CSRF) vulnerability. This is due to an issue with nonce validation in the duplicate_feed function of the plugin. It essentially allows attackers to duplicate calendar feeds if they trick an admin into clicking a malicious link.

Q: How serious is this vulnerability?

How serious is this vulnerability? The vulnerability has been given a CVSS severity score of 4.3 out of 10 by security researchers. This means it is considered a medium level risk, not critical but still quite serious. Successful exploitation could allow spammers or other malicious actors to manipulate calendar events on vulnerable sites.

Q: How can I tell if I'm affected by the vulnerability?

How can I tell if I'm affected by the vulnerability? You are affected if you are running any version of the Simple Calendar plugin prior to 3.2.5. All versions up to and including 3.2.4 contain the vulnerability. Check which version you have installed from your WordPress dashboard.

Q: What can happen if my site is vulnerable?

What can happen if my site is vulnerable? If attackers exploit this vulnerability, they could duplicate your calendar feeds, add spam events to your calendar, or cause other unintended issues. It partially depends on what calendar account your feed is synced with.

Q: How do I fix the vulnerability?

How do I fix the vulnerability? Updating to version 3.2.5 or higher will patch the vulnerability. You should update as soon as possible. In the interim, monitor your calendar closely for any suspicious behavior.

Q: Is there an alternate plugin I can use?

Is there an alternate plugin I can use? If you want to switch calendar plugins as an extra precaution, some alternatives include The Events Calendar, All-in-One Event Calendar, and Calendarize It. Always vet plugins carefully for security issues.

Q: Why wasn't this caught sooner?

Why wasn't this caught sooner? Vulnerabilities can slip through the cracks, especially in complex software. Kudos to the Simple Calendar developers for quickly releasing a patch once notified. Staying vigilant is key.

Q: How often should I update my plugins?

How often should I update my plugins? Best practice is to update your WordPress plugins whenever new versions are released, especially for security fixes. Consider enabling automatic background updates for convenience.

Q: How can I stay on top of plugin security?

How can I stay on top of plugin security? Monitor trusted sources like Wordfence regularly for vulnerability announcements. For plugins you rely on, sign up for developer notifications. Hiring a site manager is wise for busy business owners.

By Your WP Guy | October 20, 2023

Plugin Name: Simple Calendar – Google Calendar Plugin

Key Information:

Software Type: Plugin
Software Slug: google-calendar-events
Software Status: Active
Software Author: simplecalendar
Software Downloads: 2,568,146
Active Installs: 60,000
Last Updated: October 20, 2023
Patched Versions: 3.2.5
Affected Versions: <3.2.5

Vulnerability Details:

Name: Simple Calendar <= 3.2.4 - Cross-Site Request Forgery via duplicate_feed
Title: Cross-Site Request Forgery
Type: Cross-Site Request Forgery (CSRF)
CVSS Score: 4.3 (Medium)
Publicly Published: October 20, 2023
Description: The Simple Calendar – Google Calendar Plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to 3.2.5 (exclusive). This is attributed to the missing or incorrect nonce validation on the duplicate_feed function. Consequently, it's possible for unauthenticated attackers to duplicate feeds via a forged request, especially if they manage to deceive a site administrator into performing specific actions, such as clicking on a deceptive link.

Summary:

The Simple Calendar – Google Calendar Plugin for WordPress has a vulnerability in versions up to and including those before 3.2.5 that makes it susceptible to Cross-Site Request Forgery due to issues with nonce validation in the duplicate_feed function. This vulnerability has been patched in version 3.2.5.

Detailed Overview:

This vulnerability was discovered in the Simple Calendar – Google Calendar Plugin for WordPress. The issue lies within the nonce validation in the duplicate_feed function. Essentially, the plugin does not effectively validate or might entirely lack nonce validation, making the plugin susceptible to CSRF attacks. With this vulnerability, unauthenticated attackers can exploit the situation by duplicating feeds, but this would require tricking a site's administrator into clicking on a malicious link. The vulnerability is of medium severity, with a CVSS score of 4.3.

Advice for Users:

Immediate Action: Users are strongly urged to update to the patched version 3.2.5 immediately.
Check for Signs of Vulnerability: Regularly monitor your plugin's activities, and be cautious of unexpected feed duplications or any unusual behavior within the plugin.
Alternate Plugins: While a patch is available, as a precaution, users might consider other plugins offering similar functionalities.
Stay Updated: Always make sure that your plugins are updated to the most recent versions to mitigate vulnerabilities.

Conclusion:

The swift response from the plugin developers in addressing this vulnerability highlights the significance of prompt updates. To safeguard their WordPress installations, users are advised to ensure they are operating on version 3.2.5 or subsequent versions.

References:

Detailed Report:

Keeping your WordPress site and its plugins up-to-date is crucial for maintaining a secure online presence. Unfortunately, an important calendar plugin for WordPress contains a vulnerability in certain versions that could put your site at risk.

The Simple Calendar – Google Calendar Plugin, which has over 2.5 million downloads and 60,000 active installs, is susceptible to Cross-Site Request Forgery (CSRF) in versions prior to 3.2.5. This issue allows attackers to duplicate calendar feeds by tricking administrators into clicking malicious links. With a CVSS severity score of 4.3 out of 10, it is considered a medium risk vulnerability.

If you are using the Simple Calendar plugin on your WordPress site, it is highly recommended that you update to version 3.2.5 immediately. This will patch the CSRF vulnerability and secure your calendar feeds.

Here are more details on the vulnerability:

The issue lies in the nonce validation in the duplicate_feed function of the plugin. Essentially, the plugin does not properly validate or lacks nonce validation entirely, leaving it open to CSRF attacks.
With this vulnerability, an unauthenticated attacker could exploit it by duplicating feeds if they trick an administrator into clicking on a malicious link.
The vulnerability has been given a CVSS score of 4.3 out of 10, which means it is medium severity.
The vulnerability affects all versions of the plugin up to and including 3.2.4. Version 3.2.5 contains the patch.
If successfully exploited, the impact could allow attackers to duplicate calendar feeds, create spam calendar events, or other unintended consequences.

To mitigate this vulnerability:

Upgrade to version 3.2.5 of the Simple Calendar plugin immediately. This contains the fix.
Monitor your calendar feeds for any unusual duplications or behavior.
Consider switching to alternate calendar plugins as a precaution.
Make sure all your plugins stay updated to the latest versions.

This is the 3rd vulnerability found in the Simple Calendar plugin since October 2014, so staying vigilant about updates is important. As a small business owner, keeping on top of security issues like this may not be top of mind, but is vitally important to the safety and security of your website. Consider automating plugin updates or hiring a web administrator to handle technical site maintenance. The time investment is worth it to protect your online presence.

As a business owner, you don't have time to constantly monitor for WordPress vulnerabilities like this. At Your WP Guy, we become your outsourced IT team to handle security, updates, maintenance and support. Let us fully audit your site and plugins to assess any impact from this issue. We'll update everything to patched versions so you can rest easy knowing your site is locked down.

Focus on your business goals while we focus on your WordPress site's security. Chat with us anytime during business hours, schedule a call or call 678-995-5169 for a free consultation on securing your online presence.