CVE-2021-47757: Chikitsa Patient Management RCE Flaw

CVE-2021-47757 Overview

CVE-2021-47757 is an authenticated remote code execution vulnerability affecting Chikitsa Patient Management System version 2.0.2. The vulnerability exists in the backup restoration functionality, where authenticated attackers can upload a modified backup zip file containing a malicious PHP shell to execute arbitrary system commands on the server. This represents a serious security risk for healthcare organizations using this patient management system, as successful exploitation could lead to complete server compromise.

Critical Impact
Authenticated attackers can achieve remote code execution on the server by uploading malicious PHP shells through the backup restoration feature, potentially compromising sensitive patient data and healthcare infrastructure.

Affected Products

Chikitsa Patient Management System 2.0.2
Earlier versions of Chikitsa may also be affected

Discovery Timeline

2026-01-15 - CVE CVE-2021-47757 published to NVD
2026-01-16 - Last updated in NVD database

Technical Details for CVE-2021-47757

Vulnerability Analysis

This vulnerability is classified as CWE-434 (Unrestricted Upload of File with Dangerous Type). The Chikitsa Patient Management System's backup restoration functionality fails to properly validate the contents of uploaded backup zip files. An authenticated user with access to the backup restoration feature can craft a malicious backup archive containing a PHP web shell. When the backup is restored, the malicious PHP file is extracted to a web-accessible location on the server, allowing the attacker to execute arbitrary system commands.

The attack requires authentication to the application, which limits the attack surface to authorized users or attackers who have compromised valid credentials. However, once authenticated, exploitation is straightforward and requires no special conditions or user interaction beyond the attacker's own actions.

Root Cause

The root cause of this vulnerability is inadequate validation of uploaded backup files. The application accepts and processes backup zip archives without verifying the file types contained within. Specifically, the backup restoration process does not:

Validate that uploaded files match expected backup content types
Sanitize or filter executable file types such as .php files
Implement proper file type whitelisting for extracted content
Verify file signatures or checksums of backup contents

This allows attackers to inject arbitrary PHP files that will be executed when accessed via the web server.

Attack Vector

The attack is network-based and follows this exploitation pattern:

The attacker authenticates to the Chikitsa Patient Management System with valid credentials
The attacker creates or modifies a backup zip file to include a PHP web shell
Using the backup restoration feature, the attacker uploads the malicious backup archive
The application extracts the backup contents, including the PHP shell, to the web root
The attacker accesses the uploaded PHP shell via HTTP request
The web shell executes system commands with the privileges of the web server process

A public exploit is documented in Exploit-DB #50572. Additional technical information is available through the GitHub repository and SourceForge project page.

Detection Methods for CVE-2021-47757

Indicators of Compromise

Unexpected PHP files appearing in web-accessible directories after backup restoration operations
Web server logs showing requests to unusual PHP files in backup or upload directories
Process spawning activity from the web server process (e.g., www-data, apache, or nginx user)
Backup restoration events from unusual IP addresses or at unexpected times

Detection Strategies

Monitor file system changes in web directories for newly created .php files following backup operations
Implement web application firewall (WAF) rules to detect web shell signatures in HTTP responses
Deploy endpoint detection solutions to identify command execution patterns from web server processes
Review authentication logs for the backup restoration feature to identify unauthorized access attempts
Use file integrity monitoring (FIM) on critical application directories

Monitoring Recommendations

Enable detailed audit logging for all backup and restoration operations in the application
Configure alerts for any command execution originating from web server user accounts
Monitor outbound network connections from the web server for potential data exfiltration
Implement real-time alerting on file creation events in web-accessible directories

How to Mitigate CVE-2021-47757

Immediate Actions Required

Restrict access to the backup restoration feature to only essential administrative personnel
Implement network segmentation to limit access to the Chikitsa application from trusted networks only
Review recent backup restoration logs for any suspicious activity
Audit the web directories for any unauthorized PHP files or web shells
Consider temporarily disabling the backup restoration feature until a patch is available

Patch Information

As of the last NVD update on 2026-01-16, no official vendor patch has been documented for this vulnerability. Organizations should monitor the Chikitsa official website and the SourceForge project page for security updates. Contact the vendor directly for patch availability and remediation guidance.

Workarounds

Implement strict file type validation at the web server level to block execution of PHP files in backup directories
Configure the web server to deny execution of PHP files in upload and backup directories using .htaccess or server configuration
Deploy a web application firewall with rules to detect and block web shell upload attempts
Implement role-based access control to restrict backup restoration functionality to trusted administrators only
Use network-level controls to limit access to the administrative interface from specific IP addresses

bash

# Apache configuration to prevent PHP execution in backup directories
# Add to .htaccess or virtual host configuration
<Directory /path/to/chikitsa/backup>
    php_flag engine off
    <FilesMatch "\.php$">
        Require all denied
    </FilesMatch>
</Directory>