Privilege escalation vulnerabilities pose a serious threat in many applications, allowing unauthorized users to gain access to higher-level permissions. One such vulnerability is "Unauthorized Privilege Escalation via Role Manipulation." This issue arises when an application fails to enforce strict role restrictions, enabling users to manipulate their role assignments and gain elevated privileges they shouldn’t have.

This article will explore how this vulnerability works and how attackers can exploit role manipulation to escalate their access within an application.

Understanding Role-Based Access Control (RBAC)

Role-Based Access Control (RBAC) is a widely used security model designed to manage user permissions based on their assigned roles within an application. In an RBAC system, roles are predefined with specific permissions, and users are assigned to these roles according to their responsibilities.

This model helps ensure that users have access only to the resources and actions necessary for their role, maintaining a principle of least privilege.

In a well-implemented RBAC system, each role should come with strict access controls and constraints. For example:

Super Administrator: Full access to all system features and data.
Merchant Administrator: Administrative access tailored to managing company-specific operations and settings.
User: Limited access based on their specific role requirements.

When users are authorized to change roles, the system must enforce additional checks to prevent unauthorized privilege escalation. This includes validating that role changes are within acceptable boundaries and do not allow users to switch to more privileged roles without appropriate authorization.

Exploiting Role Manipulation to Escalate Privileges

Role manipulation vulnerabilities can allow attackers to gain unauthorized access by exploiting weaknesses in role validation. When these controls are not strictly enforced, attackers can exploit role manipulation vulnerabilities to escalate their privileges.

In this section, we'll see how such vulnerabilities can be exploited, specifically focusing on how attackers can leverage inadequate role validation to gain unauthorized administrative access.

Role ID Disclosure

In this vulnerability, the application exposes sensitive role information through the RetrieveAllRoles endpoint, which discloses role IDs, including that of the Super Administrator.

This exposure is a serious security risk because it allows attackers to identify and target high-privilege roles. With this information, they can manipulate their own role assignments to gain unauthorized access.

It’s crucial to review all requests carefully. In this case, the API response reveals critical role details, including the Super Administrator role ID.

{
  "roles": [
    {
      "role_id": "e9b8c5ef-9b4e-4c3e-8a2b-0b5a9e4d6f7c",
      "role_name": "Super Administrator",
      "created_at": "2024-01-15T08:00:00Z",
      "last_modified_at": "2024-09-01T10:30:00Z",
      "user_count": 1
    },
    {
      "role_id": "a3c6e1d7-4b6e-4f1b-9b3c-1a7c9d0e8f6a",
      "role_name": "Merchant Administrator",
      "created_at": "2024-02-20T09:00:00Z",
      "last_modified_at": "2024-08-15T11:00:00Z",
      "user_count": 12
    },
    {
      "role_id": "f1e8a0e7-2b6e-4b3e-9c7e-3d8a0b1e4c6f",
      "role_name": "User",
      "created_at": "2024-03-05T10:00:00Z",
      "last_modified_at": "2024-07-22T12:00:00Z",
      "user_count": 45
    },
    {
      "role_id": "b2d8a3e7-5c6e-4d2b-9a4e-1e6a9c0b7f8d",
      "role_name": "Merchant Auditor",
      "created_at": "2024-04-10T11:00:00Z",
      "last_modified_at": "2024-06-30T14:00:00Z",
      "user_count": 80
    }
  ]
}

Modifying the Update User Request

In the application, Merchant Administrators can manage user roles through the dashboard. However, from the front end, they only have the option to assign roles like User or Auditor. The Super Administrator role is deliberately hidden to prevent unauthorized changes.

Despite this front-end limitation, the underlying API request to update user roles does not enforce strict validation on role changes. This creates an opportunity for privilege escalation through direct API manipulation.

When updating user roles, the application sends a request to the updateUser endpoint. This request includes the user’s ID and the role ID they are assigned.

POST /api/updateUser HTTP/1.1
Host: chiomaibeakanma.com
Content-Type: application/json
Authorization: Bearer [token]

{
  "user_id": "user-123",
  "role_id": "f1e8a0e7-2b6e-4b3e-9c7e-3d8a0b1e4c6f"  // Original Role ID
}

Even though the Super Administrator role is not visible on the front end, the application’s back-end accepts role IDs without verifying if they should be allowed.

By intercepting and modifying this API request, an attacker can change the role ID to the Super Administrator ID obtained from the RetrieveAllRoles endpoint.

POST /api/updateUser HTTP/1.1
Host: chiomaibeakanma.com
Content-Type: application/json
Authorization: Bearer [token]

{
  "user_id": "user-123",
  "role_id": "a3c6e1d7-4b6e-4f1b-9b3c-1a7c9d0e8f6a"  // Modified to Super Administrator Role ID
}

This modification allows any user to be escalated to Super Administrator status, bypassing the intended role restrictions.

HTTP/1.1 200 OK
Content-Type: application/json

{
  "success": true,
  "message": "User role updated successfully."
}

By altering the role ID in the updateUser request, an attacker can escalate privileges to Super Administrator, gaining unrestricted access to all application features and controls.

It’s also important to note that if validation isn’t implemented properly, any user—regardless of their current role—can exploit this vulnerability.

As long as they can craft the updateUser request correctly, they can escalate their access. This underscores the importance of enforcing rigorous checks to prevent unauthorized privilege escalation.

How to Prevent Unauthorized Privilege Escalation

To address and prevent unauthorized privilege escalation via role manipulation, consider implementing the following measures:

Implement Role Validation Checks: Ensure your application enforces strict validation for role changes. Only users with the appropriate permissions should be able to assign or change roles, and the system should verify that any role changes are within acceptable boundaries.

Secure Role ID Information: Prevent the exposure of sensitive role information, such as role IDs, in API responses. Limit the role details provided to users to only what is necessary for their current permissions, minimizing the risk of exploitation.

By adopting these best practices, you'll enhance the security of your application, protecting it from unauthorized access and potential privilege escalation attacks.

Unauthorized Privilege Escalation Vulnerability via Role Manipulation

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