CVE-2021-47912
📋 TL;DR
PHP Melody 3.0 contains multiple non-persistent cross-site scripting vulnerabilities in categories, import, and user import files. Attackers can inject malicious scripts through unvalidated parameters to execute client-side attacks, potentially hijacking user sessions. This affects all users of PHP Melody version 3.0.
💻 Affected Systems
- PHP Melody
⚠️ Risk & Real-World Impact
Worst Case
Attackers could hijack administrator sessions, take full control of the PHP Melody installation, steal sensitive data, and deploy additional malware.
Likely Case
Attackers could steal user session cookies, perform actions as authenticated users, and deface website content through client-side script execution.
If Mitigated
With proper input validation and output encoding, the impact would be limited to minor UI disruption with no data compromise.
🎯 Exploit Status
Exploitation requires social engineering to trick users into clicking malicious links. No authentication needed for initial injection.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 3.0.1 or later
Vendor Advisory: https://www.phpsugar.com/blog/2021/09/php-melody-3-0-vulnerability-report-fix/
Restart Required: No
Instructions:
1. Download latest version from official PHP Melody website. 2. Backup current installation. 3. Replace vulnerable files with patched versions. 4. Verify functionality.
🔧 Temporary Workarounds
Input Validation Filter
allImplement server-side input validation for all parameters in categories, import, and user import files
Add input sanitization functions before processing user parameters
Output Encoding
allApply proper output encoding when displaying user-controlled data
Use htmlspecialchars() or similar functions for all user data output
🧯 If You Can't Patch
- Implement Web Application Firewall (WAF) rules to block XSS payloads
- Restrict access to vulnerable endpoints using IP whitelisting or authentication
🔍 How to Verify
Check if Vulnerable:
Check if running PHP Melody version 3.0. Review categories, import, and user import files for lack of input validation.Check Version:
Check PHP Melody configuration files or admin panel for version informationVerify Fix Applied:
Test vulnerable endpoints with XSS payloads. Verify proper input validation and output encoding are implemented.📡 Detection & Monitoring
Log Indicators:
- Unusual parameter values containing script tags or JavaScript in categories/import/user import requests
- Multiple failed XSS attempts
Network Indicators:
- HTTP requests with suspicious parameters containing script tags or JavaScript code
SIEM Query:
source="web_logs" AND (uri_path="/categories" OR uri_path CONTAINS "/import") AND (param_value CONTAINS "<script>" OR param_value CONTAINS "javascript:")🔗 References
- https://www.phpsugar.com/blog/2021/09/php-melody-3-0-vulnerability-report-fix/
- https://www.phpsugar.com/phpmelody.html
- https://www.vulncheck.com/advisories/php-melody-non-persistent-cross-site-scripting-via-multiple-parameters
- https://www.vulnerability-lab.com/get_content.php?id=2290
- https://www.vulnerability-lab.com/get_content.php?id=2290
