Identification Failures in Grape with Cockroachdb

An Identification Failure in a Grape API backed by Cockroachdb occurs when object-level authorization is missing or inconsistent, allowing one user to access, modify, or delete another user’s records. Because Cockroachdb is a distributed SQL database, it enforces SQL-level constraints and isolation, but it does not enforce application-level ownership. If Grape endpoints rely only on database rows matching an ID—without verifying that the row belongs to the requesting identity—an attacker can change the ID in the request and access another user’s data (Insecure Direct Object Reference / Broken Object Level Authorization).

With Grape, resource lookup is typically done in before blocks using parameters such as params[:id]. If the lookup does not scope the query to the current user, any authenticated user can enumerate or manipulate IDs. For example, a route like get '/users/:id' that runs User.find(params[:id]) without checking ownership exposes every user record that exists in the Cockroachdb table. This is an Identification Failure because the authorization check is missing, not because Cockroachdb itself is misconfigured.

Another common pattern is using UUIDs or natural keys without validating tenant or user scope. Cockroachdb will return a row if the key exists, even if it belongs to another tenant or user. In distributed deployments, consistent hashing and secondary indexes do not prevent logical access across partitions if the query does not include a tenant_id or user_id predicate. Therefore, the vulnerability arises from the application layer omitting scoping checks, while Cockroachdb simply serves the requested row.

Real-world attack patterns mirror classic OWASP API Top 10 A01:2023 broken object level authorization. Consider an endpoint intended to retrieve a user’s profile: if the Grape route uses User.find(params[:id]) without a where clause that includes the current user’s ID, an attacker can iterate through numeric or predictable UUIDs and read other profiles. This can be chained with other weaknesses such as insufficient rate limiting to perform mass enumeration. Data Exposure findings often highlight such endpoints because sensitive fields like email or phone number are returned without ownership verification.

Instrumentation and spec analysis help surface these issues. middleBrick scans the OpenAPI spec for endpoints with ID parameters and checks whether the server-side code includes authorization scoping. When runtime behavior returns data for one ID while the spec implies user-specific access, the scan reports an Identification Failure with a high severity. The scanner does not fix the code, but it provides remediation guidance, such as adding a tenant or user filter to every data access call.

To remediate Identification Failures when using Cockroachdb with Grape, always scope queries by the requesting user or tenant. Never rely on the database to enforce ownership; enforce it in the API layer before issuing SQL. Below are concrete, realistic examples that you can adapt to your schema.

1. Scoped lookup with numeric IDs

Assume a users table with columns id, email, and tenant_id. The Grape route should look up a user by ID and tenant, using the current user’s identity:

# app/api/v1/user.rb
class API::V1::User < Grape::API
  helpers do
    def current_user
      # Assume this returns an authenticated user map with :id and :tenant_id
      @current_user ||= UserAuth.find(request.env)
    end
  end

  resource :users do
    desc 'Get a user profile, scoped to the current tenant and user'
    params do
      requires :id, type: Integer, desc: 'User ID'
    end
    get ':id' do
      user = User.where(id: params[:id], tenant_id: current_user.tenant_id).first
      error!('Not found', 404) unless user
      { id: user.id, email: user.email }
    end
  end
end

This ensures that even if an attacker changes :id, Cockroachdb will return no row unless the tenant and ID match an owned record.

2. Scoped lookup with UUIDs

When using UUIDs as primary keys, include the tenant or user UUID in the WHERE clause to prevent cross-tenant reads:

# app/api/v1/profile.rb
class API::V1::Profile < Grape::API
  helpers do
    def current_profile_uuid
      request.env['HTTP_X_PROFILE_UUID']
    end

    def current_tenant_id
      request.env['X-Tenant-ID']
    end
  end

  resource :profiles do
    desc 'Retrieve a profile by UUID, ensuring tenant ownership'
    params do
      requires :profile_uuid, type: String, desc: 'Profile UUID'
    end
    get ':profile_uuid' do
      profile = Profile.where(uuid: params[:profile_uuid], tenant_id: current_tenant_id).first
      error!('Forbidden', 403) unless profile
      { uuid: profile.uuid, name: profile.name }
    end
  end
end

If your Cockroachdb schema uses secondary indexes on tenant_id and uuid, this query will be efficient and safe. The key point is that the WHERE clause must include both the identifier and the ownership predicate.

3. Batch operations and associations

When endpoints expose associations, such as a user’s posts, ensure each association is scoped:

# app/api/v1/posts.rb
class API::V1::Posts < Grape::API
  resource :users do
    params do
      requires :user_id, type: Integer
    end
    route_param :user_id do
      desc 'List posts for a user, scoped to the current tenant'
      get do
        user = User.where(id: params[:user_id], tenant_id: current_user.tenant_id).first
        error!('Forbidden', 403) unless user
        user.posts.where(tenant_id: user.tenant_id).pluck(:id, :title)
      end
    end
  end
end

Even when fetching related records, the query must include the tenant filter. Cockroachdb will use the index on (tenant_id, user_id) and then on (tenant_id, id) if those indexes exist. This prevents IDOR across tenants or users.

Finally, always validate input types and presence before using them in queries. Combine these database-side filters with application-level checks and continuous scanning using middleBrick to detect any remaining Identification Failures in Grape with Cockroachdb.