CVE-2021-20687
📋 TL;DR
This CSRF vulnerability in Kagemai 0.8.8 allows attackers to trick authenticated administrators into performing unintended actions by crafting malicious requests. Attackers can hijack administrator sessions to modify system settings, create/delete users, or alter project configurations. Only Kagemai installations with administrator accounts are affected.
💻 Affected Systems
- Kagemai
📦 What is this software?
Kagemai by Daifukuya
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise where attackers gain administrative control, modify all project data, create backdoor accounts, or delete critical information.
Likely Case
Unauthorized configuration changes, creation of privileged user accounts, or data manipulation within the ticket tracking system.
If Mitigated
No impact if proper CSRF protections are implemented or if administrators don't click malicious links while authenticated.
🎯 Exploit Status
CSRF attacks are well-understood and easy to weaponize. Requires social engineering to trick administrators.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.8.9 or later
Vendor Advisory: https://jvn.jp/en/jp/JVN11438679/index.html
Restart Required: Yes
Instructions:
1. Backup your Kagemai installation and database. 2. Download Kagemai 0.8.9 or later from official repository. 3. Replace existing installation files with patched version. 4. Restart web server. 5. Verify CSRF tokens are now properly implemented.
🔧 Temporary Workarounds
Implement CSRF Protection Middleware
allAdd custom CSRF token validation to all administrative endpoints
# Requires modifying Kagemai source code to add CSRF token validation
Use Separate Admin Browser Session
allAdministrators should use dedicated browser profiles/sessions for Kagemai administration
🧯 If You Can't Patch
- Implement web application firewall (WAF) with CSRF protection rules
- Restrict administrative access to specific IP addresses or VPN only
🔍 How to Verify
Check if Vulnerable:
Check if Kagemai version is 0.8.8. Review source code for CSRF token implementation on administrative endpoints.Check Version:
Check Kagemai configuration files or admin interface for version informationVerify Fix Applied:
Test administrative functions with missing/invalid CSRF tokens - they should be rejected. Verify version is 0.8.9 or later.📡 Detection & Monitoring
Log Indicators:
- Multiple failed administrative actions from same session
- Administrative actions without proper referrer headers
- Unusual administrative account activity
Network Indicators:
- HTTP POST requests to admin endpoints without CSRF tokens
- Requests with mismatched referrer/origin headers
SIEM Query:
source="kagemai_logs" AND (action="admin_" OR user="admin") AND status="success" AND referrer NOT CONTAINS "your-kagemai-domain"