CVE-2021-42945
📋 TL;DR
This SQL injection vulnerability in ZZCMS 2021 allows attackers to execute arbitrary SQL commands through the askbigclassid parameter in /admin/ask.php. Attackers can potentially read, modify, or delete database content, including sensitive user data. All ZZCMS 2021 installations with the vulnerable component are affected.
💻 Affected Systems
- ZZCMS
📦 What is this software?
Zzcms by Zzcms
⚠️ Risk & Real-World Impact
Worst Case
Complete database compromise leading to data theft, data destruction, authentication bypass, and potential remote code execution via database functions.
Likely Case
Unauthorized data access, privilege escalation, and potential administrative account takeover.
If Mitigated
Limited impact with proper input validation and parameterized queries in place.
🎯 Exploit Status
Proof of concept exists in GitHub repository. Exploitation requires access to the admin interface but SQL injection is straightforward once authenticated.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: http://www.zzcms.net/
Restart Required: No
Instructions:
1. Check vendor website for security updates. 2. Apply any available patches. 3. Verify fix by testing the vulnerable parameter.
🔧 Temporary Workarounds
Input Validation Filter
allAdd server-side validation to sanitize askbigclassid parameter
Modify /admin/ask.php to validate askbigclassid as integer using is_numeric() or similar function
Web Application Firewall Rule
allBlock SQL injection patterns targeting askbigclassid parameter
Add WAF rule: deny requests with SQL keywords in askbigclassid parameter
🧯 If You Can't Patch
- Restrict access to /admin/ask.php using IP whitelisting or authentication requirements
- Implement database user with minimal privileges for the application
🔍 How to Verify
Check if Vulnerable:
Test /admin/ask.php with askbigclassid parameter containing SQL injection payload like ' OR '1'='1Check Version:
Check ZZCMS version in admin panel or configuration filesVerify Fix Applied:
Test with same payload after fix - should return error or no data instead of executing SQL📡 Detection & Monitoring
Log Indicators:
- Unusual SQL errors in application logs
- Multiple failed login attempts to admin interface
- Unexpected database queries from application user
Network Indicators:
- HTTP requests to /admin/ask.php with SQL keywords in parameters
- Unusual database traffic patterns
SIEM Query:
source="web_logs" AND uri="/admin/ask.php" AND (param="askbigclassid" AND value MATCHES "(?i)(union|select|insert|update|delete|drop|or|and)")