1. Introduction
The Contact Form 7 Datepicker Plugin for WordPress is vulnerable to a stored cross-site scripting (XSS) attack. This means an attacker could inject malicious scripts into a website, potentially stealing user data or defacing the site. Systems running WordPress with this plugin installed are affected. Successful exploitation can lead to loss of confidentiality, integrity and availability.
2. Technical Explanation
The vulnerability is caused by insufficient sanitization of input data within the Contact Form 7 Datepicker Plugin for WordPress. An attacker can inject malicious JavaScript code through a form field which will then be stored and executed when other users view the affected page. The scanner has relied on self-reported version numbers, so testing was not performed directly.
- Root cause: Insufficient input validation allows unsanitized data to be stored in the plugin’s configuration.
- Exploit mechanism: An attacker submits a form with malicious JavaScript code in a date field. This code is then executed when other users view the page containing the form.
- Scope: WordPress installations using Contact Form 7 Datepicker Plugin for WordPress are affected.
3. Detection and Assessment
Confirming vulnerability involves checking the plugin version and reviewing website source code for injected scripts.
- Quick checks: Check the installed plugins list in the WordPress admin interface to confirm Contact Form 7 Datepicker Plugin is present.
- Scanning: Wordfence scanners may identify this vulnerability using signature ID 123456789 (example only).
- Logs and evidence: Review website access logs for unusual requests containing JavaScript code around form submission times.
wp plugin list | grep contact-form-7-datepicker4. Solution / Remediation Steps
The recommended solution is to remove the vulnerable plugin. This prevents further exploitation and ensures website security.
4.1 Preparation
- No services need to be stopped for this process.
- Roll back plan: Reinstall the plugin from a backup if necessary, but consider alternative plugins without known vulnerabilities.
4.2 Implementation
- Step 1: Log in to your WordPress admin interface.
- Step 2: Navigate to Plugins > Installed Plugins.
- Step 3: Locate Contact Form 7 Datepicker Plugin for WordPress and click “Deactivate”.
- Step 4: Click “Delete” to remove the plugin completely.
4.3 Config or Code Example
No config or code changes are needed; this fix involves removing the plugin.
4.4 Security Practices Relevant to This Vulnerability
Several security practices can help prevent XSS vulnerabilities.
- Safe defaults: Use secure default settings for all plugins and themes.
- Patch cadence: Regularly update WordPress core, themes, and plugins to the latest versions.
4.5 Automation (Optional)
Automation is not recommended for this specific fix due to potential disruption if other plugins are affected. Manual removal is safer.
5. Verification / Validation
Confirming the fix involves verifying that the plugin has been removed and re-testing for XSS vulnerabilities.
- Post-fix check: Check the WordPress admin interface (Plugins > Installed Plugins) to confirm Contact Form 7 Datepicker Plugin is no longer listed.
- Re-test: Attempt to submit a form with malicious JavaScript code; it should not be stored or executed on the page.
- Smoke test: Verify that other forms on your website are still functioning correctly.
- Monitoring: Monitor website access logs for any suspicious activity related to XSS attacks.
wp plugin list | grep contact-form-7-datepicker # Should return no results6. Preventive Measures and Monitoring
Preventive measures include regular security scans, input validation rules, and a robust patch management process.
- Baselines: Update your WordPress security baseline to require the latest plugin versions.
- Pipelines: Implement SAST tools in your CI/CD pipeline to scan for XSS vulnerabilities in custom code.
- Asset and patch process: Establish a regular schedule for reviewing and applying WordPress core, theme, and plugin updates.
7. Risks, Side Effects, and Roll Back
Removing the plugin may break functionality if other forms rely on it. A roll back plan is essential.
- Risk or side effect 1: Forms using Contact Form 7 Datepicker Plugin will no longer function.
- Roll back: Reinstall the plugin from a backup, but consider alternative plugins without known vulnerabilities.
8. References and Resources
Official advisories and trusted documentation are essential for staying informed about this vulnerability.
- Vendor advisory or bulletin: https://wordpress.org/plugins/contact-form-7-datepicker/
- NVD or CVE entry: CVE-2020-11516
- Product or platform documentation relevant to the fix: N/A