CVE-2021-26231
📋 TL;DR
CVE-2021-26231 is a critical SQL injection vulnerability in Fantastic Blog CMS v1.0 that allows remote attackers to execute arbitrary SQL commands via the id parameter in category.php. This affects all deployments of this specific CMS version. Attackers can potentially read, modify, or delete database content.
💻 Affected Systems
- SourceCodester Fantastic Blog CMS
📦 What is this software?
Fantastic Blog Cms by Fantastic Blog Cms Project
⚠️ Risk & Real-World Impact
Worst Case
Complete database compromise leading to data theft, data destruction, authentication bypass, and potential remote code execution if database functions allow it.
Likely Case
Database information disclosure, data manipulation, and potential privilege escalation within the application.
If Mitigated
Limited impact with proper input validation and parameterized queries preventing SQL injection.
🎯 Exploit Status
SQL injection via GET/POST parameters is well-understood and easily weaponized. Public proof-of-concept exists in GitHub repositories.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: No official vendor advisory found
Restart Required: No
Instructions:
No official patch available. Consider migrating to alternative CMS solutions or implementing custom fixes with parameterized queries.
🔧 Temporary Workarounds
Input Validation Filter
allAdd input validation to sanitize the id parameter before processing
Modify category.php to add: $id = intval($_GET['id']); // or filter_var($id, FILTER_VALIDATE_INT)
Web Application Firewall (WAF)
allDeploy WAF rules to block SQL injection patterns
Configure WAF to block SQL injection patterns in GET/POST parameters
🧯 If You Can't Patch
- Isolate the CMS instance behind a reverse proxy with strict input validation
- Implement network segmentation to limit database access from the web server
🔍 How to Verify
Check if Vulnerable:
Test by accessing category.php with SQL injection payload: /category.php?id=1' OR '1'='1Check Version:
Check CMS version in admin panel or readme filesVerify Fix Applied:
Test with same payload; should return error or no data instead of executing SQL📡 Detection & Monitoring
Log Indicators:
- Unusual SQL error messages in web logs
- Multiple requests to category.php with special characters in id parameter
Network Indicators:
- HTTP requests containing SQL keywords (UNION, SELECT, etc.) in URL parameters
SIEM Query:
web.url:*category.php* AND (web.param.id:*'* OR web.param.id:*UNION* OR web.param.id:*SELECT*)