CVE-2021-41756
📋 TL;DR
CVE-2021-41756 is a SQL injection vulnerability in dynamicMarkt marketplace software that allows attackers to execute arbitrary SQL commands through the kat parameter in index.php. This affects all users running dynamicMarkt version 3.10 or earlier. Successful exploitation could lead to data theft, data manipulation, or complete system compromise.
💻 Affected Systems
- dynamicMarkt
📦 What is this software?
Dynamicmarkt by Dynamicvision
⚠️ Risk & Real-World Impact
Worst Case
Full database compromise leading to complete data loss, privilege escalation to administrative access, and potential remote code execution on the underlying server.
Likely Case
Unauthorized access to sensitive data including user credentials, financial information, and marketplace transactions, potentially leading to data breach and business disruption.
If Mitigated
Limited impact with proper input validation and parameterized queries preventing SQL injection, though system may still be vulnerable to other attacks.
🎯 Exploit Status
Proof of concept is publicly available on GitHub. SQL injection is a well-understood attack vector with many automated tools available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: No official vendor advisory found
Restart Required: No
Instructions:
1. Check for official updates from dynamicMarkt developers
2. If no patch available, implement workarounds
3. Consider migrating to alternative software if maintenance has ceased
🔧 Temporary Workarounds
Input Validation and Sanitization
allAdd input validation and parameterized queries to the kat parameter handling in index.php
Modify index.php to use prepared statements: $stmt = $pdo->prepare('SELECT * FROM table WHERE kat = ?'); $stmt->execute([$kat]);
Web Application Firewall (WAF)
allDeploy WAF rules to block SQL injection patterns in the kat parameter
Add WAF rule: SecRule ARGS:kat "@detectSQLi" "id:1001,phase:2,deny,status:403,msg:'SQL Injection Attempt'"
🧯 If You Can't Patch
- Implement network segmentation to isolate the dynamicMarkt server from sensitive systems
- Deploy intrusion detection systems to monitor for SQL injection attempts and block malicious IPs
🔍 How to Verify
Check if Vulnerable:
Test the kat parameter with SQL injection payloads like: index.php?kat=1' OR '1'='1Check Version:
Check the software version in the admin panel or look for version files in the installation directoryVerify Fix Applied:
Test with the same SQL injection payloads and verify they are blocked or sanitized📡 Detection & Monitoring
Log Indicators:
- Unusual SQL error messages in application logs
- Multiple failed login attempts following SQL injection patterns
- Unexpected database queries
Network Indicators:
- HTTP requests with SQL keywords in kat parameter
- Unusual database connection patterns
- Traffic from known scanning tools
SIEM Query:
source="web_logs" AND (uri="*kat=*'*" OR uri="*kat=*%27*" OR uri="*kat=*SELECT*" OR uri="*kat=*UNION*")🔗 References
- https://github.com/blockomat2100/PoCs/blob/main/dynamicMarkt/vulns.md
- https://www.heise.de/download/product/dynamicmarkt-3.10-marktplatz-software-90441
- https://github.com/blockomat2100/PoCs/blob/main/dynamicMarkt/vulns.md
- https://www.heise.de/download/product/dynamicmarkt-3.10-marktplatz-software-90441
