CVE-2021-41678
📋 TL;DR
A SQL injection vulnerability in openSIS version 8.0 allows attackers to execute arbitrary SQL commands through the staff[TITLE] parameter in Staff.php. This affects all openSIS deployments using MySQL or MariaDB as the database backend. Attackers could potentially access, modify, or delete sensitive student and staff data.
💻 Affected Systems
- openSIS-Classic
📦 What is this software?
Opensis by Os4ed
⚠️ Risk & Real-World Impact
Worst Case
Complete database compromise leading to data theft, data destruction, or full system takeover via subsequent attacks.
Likely Case
Unauthorized access to sensitive student records, staff information, and potential privilege escalation within the application.
If Mitigated
Limited impact with proper input validation, parameterized queries, and database permission restrictions in place.
🎯 Exploit Status
Exploitation requires access to the vulnerable endpoint but SQL injection is well-understood and easily weaponized.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Version 8.1 or later
Vendor Advisory: https://github.com/OS4ED/openSIS-Classic/issues/203
Restart Required: No
Instructions:
1. Backup your database and application files. 2. Download and install openSIS version 8.1 or later from the official repository. 3. Follow the upgrade instructions provided by openSIS documentation.
🔧 Temporary Workarounds
Input Validation Filter
allImplement server-side input validation to sanitize the staff[TITLE] parameter before processing.
Modify /opensis/modules/users/Staff.php to add input validation for the staff[TITLE] parameter
Web Application Firewall Rule
allDeploy a WAF rule to block SQL injection patterns targeting the vulnerable endpoint.
Configure WAF to block requests containing SQL injection patterns to /opensis/modules/users/Staff.php
🧯 If You Can't Patch
- Implement strict input validation and parameterized queries in the vulnerable Staff.php file
- Restrict database user permissions to minimum required privileges and implement network segmentation
🔍 How to Verify
Check if Vulnerable:
Check if running openSIS version 8.0 with MySQL/MariaDB backend and examine Staff.php for unsanitized staff[TITLE] parameter usage.Check Version:
Check the openSIS version in the application interface or configuration files.Verify Fix Applied:
Verify version is 8.1 or later and test the vulnerable endpoint with SQL injection payloads to confirm they're blocked.📡 Detection & Monitoring
Log Indicators:
- Unusual SQL queries in database logs
- Multiple failed login attempts or parameter manipulation in web server logs for Staff.php
Network Indicators:
- HTTP requests to /opensis/modules/users/Staff.php containing SQL keywords or special characters
SIEM Query:
source="web_server" AND uri="/opensis/modules/users/Staff.php" AND (payload CONTAINS "UNION" OR payload CONTAINS "SELECT" OR payload CONTAINS "--" OR payload CONTAINS "' OR '1'='1")