CVE-2021-21917
📋 TL;DR
An authenticated SQL injection vulnerability exists in Advantech R-SeeNet's group_list page, allowing attackers to execute arbitrary SQL commands. This affects R-SeeNet 2.4.15 installations as of July 30, 2021. Attackers can exploit this through authenticated HTTP requests or cross-site request forgery.
💻 Affected Systems
- Advantech R-SeeNet
📦 What is this software?
R Seenet by Advantech
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the R-SeeNet database, allowing data theft, manipulation, or potential remote code execution on the underlying system.
Likely Case
Unauthorized data access, privilege escalation, or database manipulation by authenticated users or through CSRF attacks.
If Mitigated
Limited impact with proper input validation, parameterized queries, and network segmentation in place.
🎯 Exploit Status
Exploitation requires authentication but is straightforward via HTTP requests to the vulnerable 'ord' parameter.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.4.16 or later
Vendor Advisory: https://www.advantech.com/support
Restart Required: Yes
Instructions:
1. Download latest R-SeeNet version from Advantech support portal. 2. Backup current configuration. 3. Install update following vendor instructions. 4. Restart R-SeeNet services.
🔧 Temporary Workarounds
Input Validation Filter
allImplement web application firewall rules to filter SQL injection patterns in 'ord' parameter
WAF specific - configure to block SQL patterns in POST/GET parameters
Network Segmentation
allRestrict access to R-SeeNet web interface to authorized users only
firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="TRUSTED_IP" port protocol="tcp" port="80,443" accept'
netsh advfirewall firewall add rule name="R-SeeNet Access" dir=in action=allow protocol=TCP localport=80,443 remoteip=TRUSTED_IP
🧯 If You Can't Patch
- Implement strict input validation and parameterized queries in custom code
- Monitor for SQL injection attempts in web server logs and implement rate limiting
🔍 How to Verify
Check if Vulnerable:
Check R-SeeNet version in web interface or installation directory. Version 2.4.15 (30.07.2021) is vulnerable.Check Version:
Check web interface login page or installation directory version.txt fileVerify Fix Applied:
Verify version is 2.4.16 or later and test SQL injection attempts are blocked.📡 Detection & Monitoring
Log Indicators:
- SQL syntax errors in web server logs
- Unusual database queries from web application
- Multiple failed parameter manipulation attempts
Network Indicators:
- HTTP requests with SQL keywords in 'ord' parameter
- Unusual database connection patterns from web server
SIEM Query:
source="web_logs" AND ("ord=*SELECT*" OR "ord=*UNION*" OR "ord=*INSERT*" OR "ord=*DELETE*")