CVE-2021-43509
📋 TL;DR
This CVE describes a SQL injection vulnerability in Simple Client Management System 1.0 that allows attackers to execute arbitrary SQL commands via the id parameter in view-service.php. This affects all users running the vulnerable version of this software, potentially leading to complete database compromise.
💻 Affected Systems
- Sourcecodester Simple Client Management System
📦 What is this software?
Simple Client Management System by Simple Client Management System Project
⚠️ Risk & Real-World Impact
Worst Case
Complete database compromise including data theft, data manipulation, privilege escalation, and potential remote code execution if database functions allow it.
Likely Case
Unauthorized access to sensitive client data, database manipulation, and potential authentication bypass.
If Mitigated
Limited impact with proper input validation and parameterized queries in place.
🎯 Exploit Status
Public exploit code is available on GitHub. The vulnerability requires no authentication and is easily exploitable.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: No official vendor advisory found
Restart Required: No
Instructions:
1. Check for official patches from Sourcecodester. 2. If no patch available, implement parameterized queries in view-service.php. 3. Sanitize all user inputs, especially the id parameter. 4. Consider migrating to a different client management system.
🔧 Temporary Workarounds
Input Validation and Sanitization
allImplement strict input validation and sanitization for the id parameter in view-service.php
Modify view-service.php to use prepared statements: $stmt = $conn->prepare('SELECT * FROM services WHERE id = ?'); $stmt->bind_param('i', $_GET['id']);
Web Application Firewall (WAF)
allDeploy a WAF with SQL injection protection rules
🧯 If You Can't Patch
- Isolate the system from the internet and restrict access to authorized users only
- Implement network segmentation and monitor all database access attempts
🔍 How to Verify
Check if Vulnerable:
Test the view-service.php endpoint with SQL injection payloads in the id parameter (e.g., view-service.php?id=1' OR '1'='1)Check Version:
Check the application version in the source code or documentation filesVerify Fix Applied:
Test with SQL injection payloads and verify they are rejected or properly handled without database errors📡 Detection & Monitoring
Log Indicators:
- Unusual SQL queries in database logs
- Multiple failed login attempts or parameter manipulation in web server logs
- Database errors containing SQL syntax in application logs
Network Indicators:
- Unusual database connection patterns
- SQL injection payloads in HTTP requests to view-service.php
SIEM Query:
source=web_logs AND uri="*view-service.php*" AND (query="*' OR*" OR query="*UNION*" OR query="*SELECT*" OR query="*--*" OR query="*;*" OR query="*/*")🔗 References
- https://github.com/r4hn1/Simple-Client-Management-System-Exploit/blob/main/CVE-2021-43509
- https://r4hn1.medium.com/journey-to-first-two-cve-by-rahul-kalnarayan-307e2e87ee26
- https://github.com/r4hn1/Simple-Client-Management-System-Exploit/blob/main/CVE-2021-43509
- https://r4hn1.medium.com/journey-to-first-two-cve-by-rahul-kalnarayan-307e2e87ee26
