CVE-2021-47757
📋 TL;DR
CVE-2021-47757 is an authenticated remote code execution vulnerability in Chikitsa Patient Management System 2.0.2. Authenticated attackers can upload malicious backup files containing PHP shells to execute arbitrary commands on the server. This affects all installations running the vulnerable version of Chikitsa.
💻 Affected Systems
- Chikitsa Patient Management System
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attackers to steal sensitive patient data, install persistent backdoors, pivot to other systems, or deploy ransomware.
Likely Case
Data exfiltration of patient records and healthcare information, installation of cryptocurrency miners, or defacement of the system.
If Mitigated
Limited impact if proper file upload restrictions and authentication controls are in place, though authenticated users could still exploit.
🎯 Exploit Status
Exploit code is publicly available on Exploit-DB (ID 50572). Attack requires authenticated user credentials.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.0.3 or later
Vendor Advisory: https://www.chikitsa.io/
Restart Required: No
Instructions:
1. Backup your current installation and database. 2. Download the latest version from the official website. 3. Replace the vulnerable files with the patched version. 4. Verify the backup restoration functionality validates file types properly.
🔧 Temporary Workarounds
Disable Backup Restoration
allTemporarily disable the backup restoration functionality in the application.
# Modify application configuration to disable backup uploads
# Remove or restrict access to backup restoration pages
Implement File Upload Restrictions
linuxConfigure web server to block PHP file uploads through backup functionality.
# For Apache: Add to .htaccess or virtual host config
RewriteEngine On
RewriteCond %{REQUEST_URI} ^/backup/upload
RewriteCond %{REQUEST_FILENAME} \.php$
RewriteRule .* - [F,L]
🧯 If You Can't Patch
- Implement strict access controls to limit backup functionality to trusted administrators only.
- Deploy a web application firewall (WAF) with rules to detect and block malicious file uploads.
🔍 How to Verify
Check if Vulnerable:
Check if running Chikitsa version 2.0.2 and test if backup restoration accepts PHP files.Check Version:
Check the application's admin panel or version.txt file in the installation directory.Verify Fix Applied:
Verify version is 2.0.3 or later and test that backup restoration rejects PHP files.📡 Detection & Monitoring
Log Indicators:
- Unusual file uploads to backup directories
- PHP file execution from backup locations
- Multiple failed login attempts followed by backup uploads
Network Indicators:
- HTTP POST requests to backup upload endpoints with PHP file extensions
- Outbound connections from the server to unknown IPs after backup operations
SIEM Query:
source="web_server" AND (uri="/backup/upload" OR uri="/backup/restore") AND (file_extension="php" OR file_extension="phtml")