CVE-2024-9916: Usualtool Usualtoolcms RCE Vulnerability

CVE-2024-9916 Overview

A critical OS command injection vulnerability has been discovered in HuangDou UTCMS V9 (also known as UsualToolCMS). The vulnerability exists in the file app/modules/ut-cac/admin/cli.php, where improper handling of the o parameter allows attackers to inject and execute arbitrary operating system commands. This vulnerability can be exploited remotely without authentication, posing a significant risk to affected systems.

Critical Impact

Remote attackers can execute arbitrary OS commands on vulnerable UTCMS V9 servers through the cli.php endpoint, potentially leading to complete system compromise.

Affected Products

• UsualToolCMS Version 9.0
• HuangDou UTCMS V9
• Systems running app/modules/ut-cac/admin/cli.php module

Discovery Timeline

• 2024-10-13 - CVE-2024-9916 published to NVD
• 2024-10-16 - Last updated in NVD database

Technical Details for CVE-2024-9916

Vulnerability Analysis

This vulnerability is classified as CWE-78 (Improper Neutralization of Special Elements used in an OS Command), commonly known as OS Command Injection. The vulnerability exists within the administrative CLI module of UTCMS V9, specifically in the app/modules/ut-cac/admin/cli.php file.

The flaw stems from insufficient input validation and sanitization of the o parameter before it is passed to system command execution functions. When user-controlled input is directly incorporated into OS commands without proper escaping or validation, attackers can append malicious commands using shell metacharacters such as semicolons (;), pipes (|), or command substitution operators ($() or backticks).

The network-accessible nature of this vulnerability means that attackers can exploit it remotely without requiring any authentication or user interaction, making it particularly dangerous for internet-facing UTCMS installations.

Root Cause

The root cause of this vulnerability is improper input validation in the cli.php file. The o parameter accepts user-supplied input that is subsequently used in OS command execution without adequate sanitization. The absence of input filtering, escaping, or parameterized command execution allows malicious shell metacharacters to be interpreted by the underlying operating system shell.

Attack Vector

The attack is conducted over the network by sending a crafted HTTP request to the vulnerable cli.php endpoint. Attackers manipulate the o parameter to inject OS commands that are then executed with the privileges of the web server process.

The vulnerability requires no prior authentication and no user interaction, making it highly exploitable. Successful exploitation could allow attackers to execute arbitrary commands, read sensitive files, establish persistence, or pivot to other systems on the network.

The exploit for this vulnerability has been publicly disclosed. Technical details and proof-of-concept information are available through the GitHub CVE5-1 Documentation and VulDB #280244.

Detection Methods for CVE-2024-9916

Indicators of Compromise

• Unusual HTTP requests to app/modules/ut-cac/admin/cli.php containing shell metacharacters (;, |, &&, ||, `, $()) in the o parameter
• Web server logs showing access to the cli.php endpoint with encoded or suspicious parameter values
• Unexpected processes spawned as children of the web server process (e.g., sh, bash, cmd.exe, wget, curl)
• New or modified files in web-accessible directories or system locations
• Outbound network connections from the web server to unknown external IPs

Detection Strategies

• Deploy Web Application Firewall (WAF) rules to detect and block command injection patterns in requests to cli.php
• Implement file integrity monitoring on UTCMS installation directories to detect unauthorized modifications
• Monitor web server access logs for requests containing URL-encoded shell metacharacters targeting the ut-cac module
• Configure SIEM alerts for process creation events where the parent process is the web server

Monitoring Recommendations

• Enable verbose logging for the UTCMS application and web server to capture full request parameters
• Monitor for abnormal CPU or memory usage that may indicate command execution or cryptomining activity
• Set up alerts for any outbound connections initiated by the web server process
• Regularly review authentication logs and system access for signs of unauthorized activity

How to Mitigate CVE-2024-9916

Immediate Actions Required

• Restrict access to the app/modules/ut-cac/admin/cli.php endpoint using firewall rules or web server access controls
• If the CLI module is not required, disable or remove the ut-cac module entirely
• Implement network segmentation to limit the blast radius if exploitation occurs
• Deploy a Web Application Firewall (WAF) with command injection protection rules
• Monitor systems for indicators of compromise while awaiting an official patch

Patch Information

As of the last update on 2024-10-16, no official patch has been released by the vendor. The vendor was contacted about this disclosure but did not respond. Organizations using UTCMS V9 should implement the workarounds described below and monitor for vendor updates.

For additional technical details and vulnerability information, refer to the VulDB CTII #280244 and VulDB Submission #418748.

Workarounds

• Disable or remove the vulnerable ut-cac module if it is not essential for operations
• Implement IP-based access restrictions to limit access to administrative endpoints to trusted networks only
• Deploy input validation at the web server level to reject requests containing shell metacharacters
• Consider placing the UTCMS installation behind a reverse proxy with strict request filtering
• Evaluate migrating to an alternative CMS solution that is actively maintained and receives security updates

# Example: Restrict access to the vulnerable endpoint using Apache .htaccess
<Files "cli.php">
    Order Deny,Allow
    Deny from all
    Allow from 192.168.1.0/24
</Files>

# Example: Restrict access using Nginx location block
location ~ /ut-cac/admin/cli\.php$ {
    allow 192.168.1.0/24;
    deny all;
}