CVE-2026-24773
📋 TL;DR
CVE-2026-24773 is an Insecure Direct Object Reference (IDOR) vulnerability in Open eClass (formerly GUnet eClass) that allows unauthenticated attackers to access other users' personal files by guessing predictable user identifiers. This affects all Open eClass installations prior to version 4.2. The vulnerability exposes sensitive user data without requiring authentication.
💻 Affected Systems
- Open eClass (formerly GUnet eClass)
⚠️ Risk & Real-World Impact
Worst Case
Mass data breach where attackers systematically download all user files including sensitive documents, personal information, and course materials, potentially leading to identity theft, academic fraud, and regulatory violations.
Likely Case
Targeted data theft where attackers access specific users' files for personal information, intellectual property, or course materials, potentially leading to privacy violations and academic integrity issues.
If Mitigated
Limited data exposure if proper access controls, file encryption, and monitoring are in place, with attackers only able to access non-sensitive files.
🎯 Exploit Status
Exploitation requires guessing or enumerating user identifiers, which are often predictable (sequential IDs). No authentication required.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 4.2
Vendor Advisory: https://github.com/gunet/openeclass/security/advisories/GHSA-63pm-pff4-xc9c
Restart Required: Yes
Instructions:
1. Backup your Open eClass installation and database. 2. Download Open eClass version 4.2 from the official repository. 3. Replace existing installation files with version 4.2 files. 4. Run any database migration scripts if provided. 5. Restart the web server service.
🔧 Temporary Workarounds
Implement Access Control Middleware
allAdd server-side validation to verify user permissions before serving files
# Requires custom development - implement authentication check in file serving endpoints
Restrict File Access via Web Server
linuxConfigure web server to require authentication for file access endpoints
# Apache: Require valid-user in .htaccess for file directories
# Nginx: Add auth_basic directives for file locations
🧯 If You Can't Patch
- Implement network-level access controls to restrict file access endpoints to authenticated users only
- Monitor file access logs for unusual patterns and implement alerting for unauthorized access attempts
🔍 How to Verify
Check if Vulnerable:
Check if your Open eClass version is below 4.2 by examining the version file or admin panelCheck Version:
grep -r 'version' /path/to/openeclass/installation/ | grep -i '4\.[01]\|3\|2\|1\|0'Verify Fix Applied:
After upgrading to 4.2, attempt to access another user's file using predictable IDs while unauthenticated - access should be denied📡 Detection & Monitoring
Log Indicators:
- Multiple failed authentication attempts followed by successful file access
- File access requests with sequential user IDs from same IP
- Unauthenticated requests to user file endpoints
Network Indicators:
- HTTP GET requests to file endpoints without authentication headers
- Pattern of requests to /files/user/[sequential-numbers]
SIEM Query:
source="web_logs" AND (uri_path="/files/user/*" OR uri_path="/download/*") AND (http_status=200 OR http_status=206) AND NOT (user_agent="*bot*" OR user_agent="*crawler*") AND auth_token=""