CVE-2021-47918
📋 TL;DR
Simple CMS 2.1 contains a remote SQL injection vulnerability in the users module that allows authenticated attackers to execute arbitrary SQL commands. This can lead to complete database compromise, data theft, or web application takeover. Only Simple CMS 2.1 installations with admin access are affected.
💻 Affected Systems
- Simple CMS
⚠️ Risk & Real-World Impact
Worst Case
Complete database compromise leading to data theft, privilege escalation, remote code execution, or full web application takeover.
Likely Case
Database information disclosure, user credential theft, and potential administrative access to the CMS.
If Mitigated
Limited impact with proper input validation and database permissions, potentially only read access to non-sensitive data.
🎯 Exploit Status
Exploitation requires admin credentials but uses simple SQL injection techniques against unvalidated parameters.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: https://simplephpscripts.com/simple-cms-php
Restart Required: No
Instructions:
No official patch available. Consider upgrading to a newer version if available or implementing workarounds.
🔧 Temporary Workarounds
Input Validation and Sanitization
allAdd parameter validation and SQL injection filtering to admin.php user module parameters
Edit admin.php to add mysqli_real_escape_string() or prepared statements for all user inputs
Web Application Firewall Rules
allImplement WAF rules to block SQL injection patterns targeting the users module
Add WAF rule: deny requests containing SQL keywords (SELECT, UNION, etc.) to admin.php
🧯 If You Can't Patch
- Restrict admin.php access to specific IP addresses using .htaccess or firewall rules
- Implement database user with minimal privileges (read-only where possible) for the web application
🔍 How to Verify
Check if Vulnerable:
Check if Simple CMS version is 2.1 and review admin.php for unvalidated SQL parameters in user functionsCheck Version:
Check CMS version in admin panel or look for version information in source filesVerify Fix Applied:
Test SQL injection attempts against the users module parameters to confirm they are properly sanitized📡 Detection & Monitoring
Log Indicators:
- Multiple failed SQL queries in database logs
- Unusual admin.php access patterns
- SQL syntax errors in web server logs
Network Indicators:
- HTTP POST requests to admin.php with SQL keywords in parameters
- Unusual database connection patterns from web server
SIEM Query:
source="web_logs" AND uri="*/admin.php*" AND (param="*SELECT*" OR param="*UNION*" OR param="*OR 1=1*")