CVE-2021-40618
📋 TL;DR
This SQL injection vulnerability in openSIS Classic 8.0 allows attackers to execute arbitrary SQL commands through specific parameters in HoldAddressFields.php. This affects all users running the vulnerable version, potentially leading to unauthorized data access or system compromise.
💻 Affected Systems
- openSIS Classic
📦 What is this software?
Opensis by Os4ed
⚠️ Risk & Real-World Impact
Worst Case
Complete database compromise including sensitive student/personnel data exfiltration, authentication bypass, remote code execution, and system takeover.
Likely Case
Unauthorized access to sensitive student records, grade manipulation, personal information theft, and potential privilege escalation.
If Mitigated
Limited impact with proper input validation and database permissions, potentially only error messages or failed queries.
🎯 Exploit Status
Exploitation requires access to the application interface but no authentication. SQL injection is well-understood with many automated tools available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Version after 8.0 (check latest release)
Vendor Advisory: https://github.com/OS4ED/openSIS-Classic/issues/193
Restart Required: No
Instructions:
1. Update to the latest version of openSIS Classic. 2. Apply input validation and parameterized queries to the affected HoldAddressFields.php file. 3. Review and sanitize all user inputs in the application.
🔧 Temporary Workarounds
Input Validation Filter
allAdd input validation to filter malicious SQL characters from the vulnerable parameters
Modify HoldAddressFields.php to add: $param = preg_replace('/[^a-zA-Z0-9@._-]/', '', $_POST['parameter']);
Web Application Firewall
allDeploy WAF with SQL injection rules to block malicious requests
🧯 If You Can't Patch
- Implement strict network segmentation to isolate the openSIS server from untrusted networks
- Enable detailed SQL query logging and monitor for unusual database activity patterns
🔍 How to Verify
Check if Vulnerable:
Test the ADDR_CONT_USRN, ADDR_CONT_PSWD, SECN_CONT_USRN, or SECN_CONT_PSWD parameters in HoldAddressFields.php with SQL injection payloads like ' OR '1'='1Check Version:
Check the openSIS version in the application interface or configuration filesVerify Fix Applied:
Attempt SQL injection on the patched parameters and verify they are properly sanitized or use parameterized queries📡 Detection & Monitoring
Log Indicators:
- Unusual SQL queries in database logs
- Multiple failed login attempts with SQL syntax
- Requests to HoldAddressFields.php with special characters
Network Indicators:
- HTTP POST requests to HoldAddressFields.php containing SQL keywords
- Unusual database connection patterns from application server
SIEM Query:
source="web_logs" AND uri="*HoldAddressFields.php*" AND (request="*' OR*" OR request="*UNION*" OR request="*SELECT*" OR request="*INSERT*")