CVE-2024-27710

Executive Summary

CVE-2024-27710 is a privilege escalation vulnerability in Eskooly Free Online School Management Software version 3.0 and earlier. The flaw resides in the authentication mechanism, allowing a remote attacker to bypass normal authentication controls and escalate their privileges to an administrative level. This could lead to full compromise of the school management system, including access to sensitive student, staff, and financial data. No public proof-of-concept (PoC) or patch is currently available, making this a high-risk, unpatched vulnerability.

Supply Chain & Package Security

This vulnerability is not associated with an NPM, PyPI, Go, or Ruby package. It is a standalone web application vulnerability in the Eskooly software.

CVSS Breakdown & Threat Level

The CVSS score is listed as 0.0, indicating insufficient data for a full CVSS calculation. However, based on the description and impact, a reasonable estimated vector would be:

• Attack Vector (AV): Network (N) – exploitable remotely.
• Attack Complexity (AC): Low (L) – likely simple manipulation of authentication requests.
• Privileges Required (PR): None (N) – no prior authentication needed.
• User Interaction (UI): None (N) – no user action required.
• Scope (S): Unchanged (U) – the vulnerable component is the only affected system.
• Confidentiality (C): High (H) – full access to sensitive data.
• Integrity (I): High (H) – ability to modify data and configurations.
• Availability (A): High (H) – potential to disrupt service.

Estimated CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Estimated Score: 9.8 (Critical)

Deep Dive & Mechanics

The vulnerability is a classic authentication bypass leading to privilege escalation. The exact mechanism is not publicly documented, but based on the description, it likely involves one of the following:

1. Insecure Direct Object Reference (IDOR) in Authentication: The application may use predictable or user-controlled parameters (e.g., user_id, role) during the authentication process. An attacker could manipulate these parameters to assume an administrative role without valid credentials.
2. Session Fixation/Prediction: The application might generate weak or predictable session tokens. An attacker could hijack an existing admin session or forge a token to gain elevated privileges.
3. Missing Authorization Checks: After initial authentication (even as a low-privilege user), the application may fail to properly verify authorization for administrative functions. An attacker could directly access admin endpoints (e.g., /admin/dashboard) without proper session validation.
4. SQL Injection in Login: The login form might be vulnerable to SQL injection, allowing an attacker to bypass authentication entirely and log in as any user, including an admin.

The core issue is a failure in the authentication and authorization logic, allowing an unauthenticated or low-privileged user to gain administrative access.

Vulnerable vs. Patched Code

No patch is available. The vulnerable code is presumed to be in the authentication module of Eskooly v3.0 and earlier. A patched version would need to implement:

• Strict Server-Side Validation: All authentication and authorization checks must be performed server-side, not relying on client-side parameters.
• Secure Session Management: Use cryptographically random, unpredictable session tokens with proper expiration and rotation.
• Role-Based Access Control (RBAC): Enforce strict RBAC on every administrative endpoint, verifying the user's role before granting access.
• Input Sanitization: Sanitize all user inputs to prevent SQL injection and other injection attacks.

Example of vulnerable code (conceptual PHP):

// Vulnerable: relies on user-supplied 'role' parameter
$role = $_POST['role'];
if ($role == 'admin') {
    // Grant admin privileges
    $_SESSION['role'] = 'admin';
}

Example of patched code (conceptual PHP):

// Patched: role is determined server-side after authentication
$user = authenticate_user($_POST['username'], $_POST['password']);
if ($user && $user['role'] == 'admin') {
    $_SESSION['role'] = 'admin';
} else {
    // Deny access
}

Exploitation & Lab Setup

Red Team

Objective: Gain administrative access to the Eskooly system.

Lab Setup:

1. Deploy a local instance of Eskooly v3.0 (if available) or use a vulnerable target.
2. Use a web proxy (e.g., Burp Suite, OWASP ZAP) to intercept and modify HTTP requests.

Exploitation Steps:

1. Reconnaissance: Identify the login page and any administrative endpoints (e.g., /admin, /dashboard).
2. Parameter Manipulation: Attempt to modify parameters in the login request. For example, change role=user to role=admin or user_id=1 to user_id=0.
3. Direct Endpoint Access: Try to access admin URLs directly without authentication (e.g., https://target.com/admin/users.php).
4. Session Prediction: If session tokens are predictable (e.g., sequential numbers), try to brute-force or guess an admin's session ID.
5. SQL Injection: Test the login form for SQL injection by entering payloads like ' OR '1'='1 in the username field.

Example Burp Suite Request Modification:

POST /login.php HTTP/1.1
Host: target.com
Content-Type: application/x-www-form-urlencoded

username=attacker&password=attacker&role=admin

Blue Team

Objective: Detect and prevent exploitation of this vulnerability.

Detection Steps:

1. Monitor Authentication Logs: Look for unusual patterns, such as multiple failed login attempts followed by a successful login with an elevated role.
2. Analyze HTTP Requests: Check for requests with modified parameters (e.g., role=admin) or direct access to admin endpoints from non-admin IPs.
3. Session Anomaly Detection: Alert on session tokens that are reused or appear to be brute-forced.
4. Web Application Firewall (WAF) Rules: Implement rules to block SQL injection attempts and parameter tampering.

Mitigation Steps:

1. Immediate Patching: If a patch becomes available, apply it immediately. Since none exists, consider isolating the application or taking it offline.
2. Virtual Patching: Use a WAF to create virtual patches that block known attack patterns (e.g., blocking requests with role=admin in POST data).
3. Network Segmentation: Place the Eskooly server in a segmented network with strict access controls.
4. Enhanced Monitoring: Increase logging and monitoring for the Eskooly application, focusing on authentication events.

Indicators of Compromise (IOCs)

• Network IOCs:
  • HTTP requests to /login.php or /admin/ with modified parameters (e.g., role=admin, user_id=0).
  • Multiple rapid requests to different admin endpoints from a single IP.
  • SQL injection patterns in login requests (e.g., ' OR '1'='1).
• Host IOCs:
  • Unauthorized creation of new admin users in the database.
  • Changes to user roles or permissions in the application logs.
  • Unexpected access to sensitive files (e.g., /etc/passwd, database dumps).
• Log IOCs:
  • Authentication logs showing a user logging in with a role that does not match their credentials.
  • Web server logs showing 200 OK responses for admin endpoints from non-admin IPs.
  • Database logs showing suspicious queries (e.g., SELECT * FROM users WHERE username = 'admin' --).

Detection Engineering

YARA Rule

rule Detect_Eskooly_Privilege_Escalation_Attempt {
    meta:
        description = "Detects HTTP requests attempting to exploit CVE-2024-27710 in Eskooly"
        author = "Valters IT"
        date = "2024-10-27"
        reference = "CVE-2024-27710"
    strings:
        $s1 = "role=admin" nocase
        $s2 = "user_id=0" nocase
        $s3 = "user_id=1" nocase
        $s4 = "/admin/" nocase
        $s5 = "SQL injection" nocase
    condition:
        any of ($s1, $s2, $s3) or ($s4 and #s5 > 0)
}

Sigma Rule

title: Eskooly Privilege Escalation Attempt
id: 7a8b9c0d-1e2f-3a4b-5c6d-7e8f9a0b1c2d
status: experimental
description: Detects potential exploitation of CVE-2024-27710 in Eskooly
author: Valters IT
date: 2024-10-27
logsource:
    category: webserver
    product: apache
    service: accesslog
detection:
    selection:
        cs-method: 'POST'
        cs-uri-stem: '/login.php'
        cs-uri-query|contains: 'role=admin'
    condition: selection
falsepositives:
    - Legitimate admin login attempts (rare)
level: high

Suricata Rule

alert http $HOME_NET any -> $EXTERNAL_NET any (
    msg:"CVE-2024-27710 - Eskooly Privilege Escalation Attempt";
    flow:to_server,established;
    content:"POST"; http_method;
    content:"/login.php"; http_uri;
    content:"role=admin"; http_client_body;
    classtype:attempted-admin;
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

1. Immediate Action: Since no patch is available, the Eskooly application should be taken offline or isolated from the network until a fix is released.
2. Virtual Patching: Deploy a WAF with rules to block the identified attack patterns (e.g., parameter tampering, direct admin endpoint access).
3. Code Review: If source code is available, conduct a thorough review of the authentication and authorization logic. Implement server-side validation and secure session management.
4. User Education: Inform all users of the risk and advise them to change passwords immediately if the system is still in use.
5. Monitoring: Implement the detection rules provided above to monitor for any exploitation attempts.
6. Vendor Contact: Contact Eskooly for an official patch or mitigation guidance. If no response, consider migrating to a different, more secure school management solution.

Valters IT
Securing Digital Frontiers