CVE-2024-13551
📋 TL;DR
The ABC Notation WordPress plugin has a stored cross-site scripting vulnerability that allows authenticated attackers with contributor-level access or higher to inject malicious scripts via the 'abcjs' shortcode. These scripts execute whenever users view compromised pages, potentially stealing credentials or performing unauthorized actions. All WordPress sites using ABC Notation plugin versions up to 6.1.3 are affected.
💻 Affected Systems
- ABC Notation WordPress Plugin
📦 What is this software?
Abc Notation by Paulrosen
⚠️ Risk & Real-World Impact
Worst Case
Attackers could steal administrator credentials, take over the WordPress site, deface pages, redirect visitors to malicious sites, or install backdoors for persistent access.
Likely Case
Attackers with contributor access inject malicious scripts that steal user session cookies, perform actions as logged-in users, or display phishing content to visitors.
If Mitigated
With proper user access controls and content review processes, the impact is limited to potential defacement of individual pages by rogue contributors.
🎯 Exploit Status
Exploitation requires contributor-level WordPress access. The vulnerability is in the shortcode handler, making injection straightforward once authenticated.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 6.1.4 or later
Vendor Advisory: https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=3169965%40abc-notation&new=3169965%40abc-notation&sfp_email=&sfph_mail=
Restart Required: No
Instructions:
1. Log into WordPress admin panel. 2. Navigate to Plugins → Installed Plugins. 3. Find ABC Notation plugin. 4. Click 'Update Now' if update available. 5. If no update appears, manually download version 6.1.4+ from WordPress.org and replace plugin files.
🔧 Temporary Workarounds
Remove Contributor Shortcode Access
allRestrict contributor users from using the abcjs shortcode by modifying user capabilities or using content filters.
Add to theme functions.php or custom plugin: add_filter('user_has_cap', 'restrict_abcjs_shortcode', 10, 3); function restrict_abcjs_shortcode($allcaps, $caps, $args) { if (isset($args[0]) && $args[0] === 'edit_posts' && current_user_can('contributor')) { $allcaps['unfiltered_html'] = false; } return $allcaps; }
🧯 If You Can't Patch
- Remove ABC Notation plugin entirely if not essential
- Downgrade contributor users to subscriber role to prevent exploitation
🔍 How to Verify
Check if Vulnerable:
Check WordPress admin → Plugins → Installed Plugins for ABC Notation version. If version is 6.1.3 or lower, you are vulnerable.Check Version:
wp plugin get abc-notation --field=version (if WP-CLI installed)Verify Fix Applied:
After update, verify ABC Notation plugin shows version 6.1.4 or higher in WordPress plugins list.📡 Detection & Monitoring
Log Indicators:
- Unusual post/page edits by contributor users
- Multiple failed login attempts followed by successful contributor login
- Posts/pages containing suspicious script tags or encoded payloads
Network Indicators:
- Outbound connections to suspicious domains from your WordPress site
- Unexpected JavaScript loading from post/page content
SIEM Query:
source="wordpress" AND (event="post_updated" OR event="page_updated") AND user_role="contributor" AND content CONTAINS "<script>" OR content CONTAINS "javascript:"