CVE-2023-4308
📋 TL;DR
The User Submitted Posts WordPress plugin has a stored XSS vulnerability that allows unauthenticated attackers to inject malicious scripts into website content. When users view pages containing the injected scripts, their browsers execute the attacker's code. This affects all WordPress sites using vulnerable versions of the plugin.
💻 Affected Systems
- User Submitted Posts WordPress Plugin
📦 What is this software?
User Submitted Posts by Plugin Planet
⚠️ Risk & Real-World Impact
Worst Case
Attackers could steal administrator credentials, deface websites, redirect users to malicious sites, or install backdoors for persistent access.
Likely Case
Attackers inject malicious scripts to steal user session cookies, redirect visitors to phishing pages, or display unwanted advertisements.
If Mitigated
With proper input validation and output escaping, malicious scripts are neutralized before reaching users' browsers.
🎯 Exploit Status
Exploitation requires submitting malicious content through the plugin's user submission form.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions after 20230809
Vendor Advisory: https://plugins.trac.wordpress.org/changeset/2952471/user-submitted-posts
Restart Required: No
Instructions:
1. Log into WordPress admin panel. 2. Navigate to Plugins > Installed Plugins. 3. Find 'User Submitted Posts'. 4. Click 'Update Now' if available. 5. Alternatively, download latest version from WordPress plugin repository and manually update.
🔧 Temporary Workarounds
Disable User Submissions
allTemporarily disable the user submission functionality until patched.
Navigate to WordPress admin > Settings > User Submitted Posts > Disable submission form
Web Application Firewall Rules
allAdd WAF rules to block XSS payloads in user-submitted-content parameter.
Add rule: Block requests containing <script> tags in user-submitted-content parameter
🧯 If You Can't Patch
- Disable the User Submitted Posts plugin completely
- Implement strict Content Security Policy headers to limit script execution
🔍 How to Verify
Check if Vulnerable:
Check WordPress admin > Plugins > Installed Plugins > User Submitted Posts version number.Check Version:
wp plugin list --name='user-submitted-posts' --field=versionVerify Fix Applied:
Verify plugin version is newer than 20230809 and test submission form with XSS payloads.📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to submission endpoint with script tags
- Multiple submissions from same IP with encoded payloads
Network Indicators:
- HTTP POST requests containing <script> tags in user-submitted-content parameter
SIEM Query:
source="web_logs" AND ("user-submitted-content" AND ("<script>" OR "javascript:" OR "onerror="))🔗 References
- https://plugins.trac.wordpress.org/changeset/2952471/user-submitted-posts
- https://www.wordfence.com/threat-intel/vulnerabilities/id/3bb4d37c-c4c2-4523-9b4e-73ffb7be81ea?source=cve
- https://plugins.trac.wordpress.org/changeset/2952471/user-submitted-posts
- https://www.wordfence.com/threat-intel/vulnerabilities/id/3bb4d37c-c4c2-4523-9b4e-73ffb7be81ea?source=cve
