CVE-2020-21725
📋 TL;DR
OpenSNS v6.1.0 contains a blind SQL injection vulnerability in the ChinaCityController component via the pid parameter. This allows attackers to execute arbitrary SQL commands on the database without authentication. All systems running the vulnerable version are affected.
💻 Affected Systems
- OpenSNS
📦 What is this software?
Opensns by Opensns
⚠️ Risk & Real-World Impact
Worst Case
Complete database compromise leading to data theft, data destruction, or full system takeover via SQL injection to RCE chaining.
Likely Case
Database information disclosure, data manipulation, or potential privilege escalation.
If Mitigated
Limited impact with proper input validation and database permissions restricting damage to non-critical data.
🎯 Exploit Status
Blind SQL injection requires time-based or boolean techniques but is well-documented. Public proof-of-concept exists in GitHub references.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: No official vendor advisory found
Restart Required: No
Instructions:
1. Check for official OpenSNS patches or updates. 2. If unavailable, implement workarounds. 3. Manually patch the vulnerable file by adding proper input validation and parameterized queries.
🔧 Temporary Workarounds
Input Validation Filter
allAdd server-side validation to ensure pid parameter contains only numeric values
Modify /Controller/ChinaCityController.class.php to validate pid parameter before processing
Web Application Firewall Rule
allBlock SQL injection patterns in requests to ChinaCityController
Add WAF rule: deny requests to *ChinaCityController* containing SQL keywords like UNION, SELECT, INSERT, etc.
🧯 If You Can't Patch
- Implement network segmentation to restrict access to the vulnerable endpoint
- Deploy a web application firewall with SQL injection protection rules
🔍 How to Verify
Check if Vulnerable:
Check if OpenSNS version is 6.1.0 and if /Controller/ChinaCityController.class.php exists without proper input validation for pid parameterCheck Version:
Check OpenSNS configuration files or admin panel for version informationVerify Fix Applied:
Test the vulnerable endpoint with SQL injection payloads and verify they are blocked or sanitized📡 Detection & Monitoring
Log Indicators:
- Unusual SQL errors in application logs
- Multiple requests to ChinaCityController with suspicious pid parameters
- Time-delayed responses indicating blind SQL injection
Network Indicators:
- HTTP requests to */Controller/ChinaCityController.class.php* with SQL injection patterns in parameters
- Unusual database query patterns from application server
SIEM Query:
source="web_logs" AND uri="*ChinaCityController*" AND (param="*pid=*UNION*" OR param="*pid=*SELECT*" OR param="*pid=*SLEEP*")