CVE-2021-27915
📋 TL;DR
CVE-2021-27915 is a cross-site scripting (XSS) vulnerability in Mautic's description fields that allows authenticated users with appropriate permissions to inject malicious scripts. If exploited, this could lead to privilege escalation within the Mautic application. This affects all Mautic installations running vulnerable versions.
💻 Affected Systems
- Mautic
📦 What is this software?
Mautic by Acquia
Mautic by Acquia
Mautic by Acquia
Mautic by Acquia
Mautic by Acquia
Mautic by Acquia
Mautic by Acquia
Mautic by Acquia
Mautic by Acquia
⚠️ Risk & Real-World Impact
Worst Case
An authenticated malicious user could execute arbitrary JavaScript in the context of other users' sessions, potentially stealing session cookies, performing actions as other users, or gaining administrative access to the Mautic instance.
Likely Case
An authenticated user with content creation permissions could inject malicious scripts into description fields, affecting other users who view those fields, potentially leading to session hijacking or unauthorized actions.
If Mitigated
With proper input validation and output encoding, malicious scripts would be neutralized, preventing any exploitation.
🎯 Exploit Status
Exploitation requires authenticated access and appropriate permissions. The advisory includes technical details that could facilitate exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 3.3.4
Vendor Advisory: https://github.com/mautic/mautic/security/advisories/GHSA-2rc5-2755-v422
Restart Required: No
Instructions:
1. Backup your Mautic installation and database. 2. Update Mautic to version 3.3.4 or later via the built-in updater or manual installation. 3. Verify the update was successful by checking the version in the Mautic dashboard.
🔧 Temporary Workarounds
Input Validation and Output Encoding
allImplement strict input validation and proper output encoding for all description fields in custom templates.
Restrict User Permissions
allLimit user permissions to only necessary functions and regularly audit user access levels.
🧯 If You Can't Patch
- Implement a web application firewall (WAF) with XSS protection rules
- Disable or restrict access to description field editing for non-essential users
🔍 How to Verify
Check if Vulnerable:
Check Mautic version in the dashboard or via the command line: php app/console mautic:versionCheck Version:
php app/console mautic:versionVerify Fix Applied:
Verify the version is 3.3.4 or higher and test description fields for script injection attempts.📡 Detection & Monitoring
Log Indicators:
- Unusual script tags or JavaScript in description field updates
- Multiple failed login attempts followed by description field modifications
Network Indicators:
- HTTP requests containing script tags in description field parameters
SIEM Query:
source="mautic_logs" AND (description_field CONTAINS "<script>" OR description_field CONTAINS "javascript:")