CVE-2024-4655
📋 TL;DR
The Ultimate Blocks WordPress plugin before version 3.1.9 has a stored cross-site scripting (XSS) vulnerability. Users with contributor role or higher can inject malicious scripts into posts/pages, which execute when other users view that content. This affects WordPress sites using vulnerable versions of the plugin.
💻 Affected Systems
- Ultimate Blocks WordPress Plugin
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers with contributor access could steal administrator session cookies, redirect users to malicious sites, or deface the website by injecting persistent malicious scripts.
Likely Case
Malicious contributors could embed scripts that steal user session data or perform actions on behalf of authenticated users.
If Mitigated
With proper user role management and content review processes, the impact is limited to potential data leakage from users viewing malicious content.
🎯 Exploit Status
Exploitation requires contributor-level access. The vulnerability is in block option handling where input isn't properly sanitized before output.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 3.1.9
Vendor Advisory: https://wpscan.com/vulnerability/a0dc73b3-3c51-4d03-963f-00fa7d8b0d51/
Restart Required: No
Instructions:
1. Log into WordPress admin panel. 2. Go to Plugins → Installed Plugins. 3. Find Ultimate Blocks plugin. 4. Click 'Update Now' if update available. 5. If no update shows, manually update to version 3.1.9 or later.
🔧 Temporary Workarounds
Disable Ultimate Blocks Plugin
allTemporarily disable the vulnerable plugin until patched
wp plugin deactivate ultimate-blocks
Restrict Contributor Role
allTemporarily remove contributor role permissions or elevate to higher trust level
🧯 If You Can't Patch
- Implement strict content review process for all contributor submissions
- Add web application firewall (WAF) rules to block XSS payloads
🔍 How to Verify
Check if Vulnerable:
Check WordPress admin → Plugins → Ultimate Blocks → Version number. If version is below 3.1.9, you are vulnerable.Check Version:
wp plugin get ultimate-blocks --field=versionVerify Fix Applied:
After updating, verify Ultimate Blocks plugin version shows 3.1.9 or higher in WordPress admin.📡 Detection & Monitoring
Log Indicators:
- Unusual post/page edits by contributors
- Script tags in post content from contributor users
Network Indicators:
- Outbound connections to suspicious domains from WordPress pages
SIEM Query:
source="wordpress" AND (event="post_updated" OR event="page_updated") AND user_role="contributor" AND content CONTAINS "<script>"