CVE-2020-21377
📋 TL;DR
This CVE describes a critical SQL injection vulnerability in yunyecms V2.0.1 that allows attackers to execute arbitrary SQL commands via the selcart parameter. This affects all deployments using the vulnerable version of yunyecms, potentially compromising the entire database and application. Attackers can exploit this without authentication to steal, modify, or delete sensitive data.
💻 Affected Systems
- yunyecms
📦 What is this software?
Yunyecms by Yunyecms
⚠️ Risk & Real-World Impact
Worst Case
Complete database compromise leading to data theft, data destruction, privilege escalation to admin accounts, and potential remote code execution through database functions.
Likely Case
Unauthenticated attackers extracting sensitive user data, administrative credentials, and manipulating database content.
If Mitigated
Attack attempts are blocked at the web application firewall level, preventing SQL injection payloads from reaching the vulnerable parameter.
🎯 Exploit Status
The vulnerability is simple to exploit with standard SQL injection techniques. Public issue tracker contains technical details that can be easily weaponized.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: https://gitee.com/yunyecms/yunyecms/issues/I15J32
Restart Required: No
Instructions:
1. Check the yunyecms issue tracker for official patches. 2. If no patch available, consider upgrading to a newer version if compatible. 3. Apply input validation and parameterized queries to the selcart parameter handler.
🔧 Temporary Workarounds
Web Application Firewall (WAF) Rules
allDeploy WAF rules to block SQL injection patterns targeting the selcart parameter
Input Validation Filter
allAdd server-side validation to reject suspicious characters in the selcart parameter
🧯 If You Can't Patch
- Implement strict input validation and sanitization for the selcart parameter
- Deploy a web application firewall with SQL injection protection rules
🔍 How to Verify
Check if Vulnerable:
Test by sending SQL injection payloads to endpoints using the selcart parameter and observing database errors or unexpected behavior.Check Version:
Check yunyecms version in admin panel or configuration filesVerify Fix Applied:
Attempt SQL injection attacks against the selcart parameter and verify they are properly rejected or sanitized.📡 Detection & Monitoring
Log Indicators:
- Unusual database error messages in web logs
- Multiple requests with SQL keywords in selcart parameter
- Requests with unusual length or special characters in selcart
Network Indicators:
- HTTP requests containing SQL injection patterns in URL parameters
- Unusual database connection patterns from web server
SIEM Query:
web_logs | where url contains "selcart" and (url contains "union" or url contains "select" or url contains "' OR" or url contains "--" or url contains ";")