1. Introduction
The FeedList Plugin for WordPress ‘i’ Parameter XSS vulnerability allows an attacker to inject malicious code into a website, potentially compromising user data and site integrity. This affects websites using the vulnerable plugin version and poses a Medium severity risk to confidentiality, integrity, and availability.
2. Technical Explanation
The FeedList plugin for WordPress does not properly sanitize input provided to the ‘i’ parameter of the ‘handler_image.php’ script. This allows an attacker to inject arbitrary HTML or JavaScript code that will be executed in a user’s browser when they view content generated by the affected script. The vulnerability requires a user to access a webpage where the vulnerable plugin is used to display images.
- Root cause: Missing input validation on the ‘i’ parameter of the ‘handler_image.php’ script.
- Exploit mechanism: An attacker crafts a malicious URL containing JavaScript code in the ‘i’ parameter, which is then reflected back to the user’s browser and executed. For example:
http://example.com/wp-content/plugins/feedlist/handler_image.php?i= - Scope: WordPress websites using FeedList plugin versions prior to 2.70.00 are affected.
3. Detection and Assessment
You can confirm if your system is vulnerable by checking the installed version of the FeedList plugin or scanning for the vulnerability signature.
- Quick checks: Check the WordPress plugins page in the admin interface to see the installed version of FeedList.
- Scanning: Nessus, OpenVAS and other scanners may detect this vulnerability with ID 44704. These are examples only.
- Logs and evidence: Review web server access logs for requests to ‘handler_image.php’ containing suspicious characters or script tags in the ‘i’ parameter.
wp plugin list | grep feedlist4. Solution / Remediation Steps
Upgrade the FeedList plugin to a patched version to resolve this vulnerability.
4.1 Preparation
- No services need to be stopped for this update.
- Roll back plan: If the upgrade causes issues, restore from the backup created in step 1.
4.2 Implementation
- Step 1: Log into your WordPress admin interface.
- Step 2: Navigate to ‘Plugins’ -> ‘Installed Plugins’.
- Step 3: Locate the FeedList plugin.
- Step 4: If an update is available, click ‘Update Now’. Alternatively, download version 2.70.00 or later from the WordPress plugin repository and upload it via ‘Add New’ -> ‘Upload Plugin’.
- Step 5: Activate the updated plugin.
4.3 Config or Code Example
No configuration changes are required; only a plugin update is needed.
Before
After
4.4 Security Practices Relevant to This Vulnerability
- Patch cadence: Regularly update plugins, themes, and WordPress core to address known vulnerabilities promptly.
4.5 Automation (Optional)
No automation is recommended for this specific vulnerability.
5. Verification / Validation
Confirm the fix by verifying that the plugin has been updated to a patched version and re-testing the exploit attempt.
- Post-fix check: Check the WordPress plugins page in the admin interface to confirm FeedList is at version 2.70.00 or later.
- Re-test: Attempt the exploit URL from section 2 (
http://example.com/wp-content/plugins/feedlist/handler_image.php?i=). The script should not execute, and no alert box should appear. - Monitoring: Monitor web server logs for any further attempts to exploit this vulnerability.
wp plugin list | grep feedlist6. Preventive Measures and Monitoring
- Baselines: Include FeedList in your WordPress security baseline, specifying the minimum acceptable version (2.70.00 or later).
- Asset and patch process: Implement a regular schedule for reviewing and updating all WordPress plugins.
7. Risks, Side Effects, and Roll Back
- Risk or side effect 1: Plugin updates can sometimes cause compatibility issues with other plugins or themes. Test the update in a staging environment first.
- Roll back: If the update causes issues, restore your WordPress website from the backup created in section 4.1.
8. References and Resources
- Vendor advisory or bulletin: https://plugins.trac.wordpress.org/changeset/664535/feedlist
- NVD or CVE entry: CVE-2010-4637
- Product or platform documentation relevant to the fix: https://packetstormsecurity.com/1011-exploits/wpfeedlist-xss.txt