Broken Access Control in Loopback with Cockroachdb

Broken Access Control in a Loopback application backed by Cockroachdb commonly occurs when authorization checks are missing or improperly enforced at the data-access layer. Because Loopback models typically map directly to database tables or views, developers may assume that database permissions alone are sufficient. Relying on Cockroachdb row-level security (RLS) without corresponding application-level checks can still allow an authenticated user to manipulate model methods or REST endpoints to access or modify records that belong to another tenant or role.

For example, consider a Loopback model Project mapped to a Cockroachdb table projects that includes a tenant_id column for multi-tenancy. If the model exposes a built-in REST endpoint like /api/projects/{id} and the data source connects with a highly privileged Cockroachdb user, an attacker who can guess or obtain another project’s ID can read or update that record. This happens because the endpoint does not enforce tenant ownership or role-based checks before issuing queries such as Project.find({ where: { id: req.params.id } }). The vulnerability is compounded when combined with BOLA/IDOR checks in middleBrick scanning, which will flag missing ownership validation and over-privileged database service accounts.

Cockroachdb features like role-based privileges and RLS are powerful, but they do not automatically protect application-specific access rules. A common misconfiguration is to grant the Loopback app a Cockroachdb role that has broad SELECT, INSERT, UPDATE, and DELETE rights, then rely on ad-hoc JavaScript checks that can be bypassed if the API path is not properly guarded. middleBrick’s checks for Authentication, BOLA/IDOR, and Property Authorization highlight these gaps by correlating the unauthenticated or insufficiently constrained API surface with the database permissions schema. Without per-request tenant validation and least-privilege database roles, the attack surface remains large, and findings will point to missing or misapplied authorization controls at the model and endpoint level.

To remediate Broken Access Control in Loopback with Cockroachdb, enforce tenant and role checks at the model or repository level before any database operation. Use Loopback’s built-in context and hooks to inject the current user’s identity and tenant scope, and ensure that the Cockroachdb user your application uses follows the principle of least privilege.

First, define a repository mixin or operation hook that appends tenant and ownership filters to every query. For example, in server/models/project.js, you can set a model hook to inject tenant_id constraints based on the authenticated user:

module.exports = function (Project) {
  Project.observe('before save', function filterTenant(ctx, next) {
    const { currentUser } = ctx.options;
    if (!currentUser) return next(new Error('AUTH_REQUIRED'));
    // Ensure every write applies tenant isolation
    if (ctx.instance) {
      ctx.instance.tenant_id = currentUser.tenant_id;
    } else if (ctx.where) {
      ctx.where.tenant_id = currentUser.tenant_id;
    }
    next();
  });
};

Second, avoid using a highly privileged Cockroachdb user for the data source. Instead, create a dedicated database role per tenant or use a parameterized role pattern, and configure the Loopback datasource to connect without broad rights. In server/datasources.local.js, define the connection with strict settings:

module.exports = {
  cockroachdb: {
    connector: 'cockroachdb',
    host: 'your-cockroachdb-host',
    port: 26257,
    database: 'api_db',
    user: 'loopback_app',
    password: process.env.COCKROACH_PASSWORD,
    schema: 'public',
    // Disable any implicit schema-wide permissions in the app layer
    options: {
      ssl: { rejectUnauthorized: false }
    }
  }
};

Third, explicitly scope model queries in your Loopback code to include tenant and role checks. For example, when retrieving a project by ID, always include the tenant context:

const project = await Project.findOne({
  where: {
    id: req.params.id,
    tenant_id: req.accessToken.user.tenant_id
  },
  include: {
    relation: 'owner',
    scope: {
      where: {
        tenant_id: req.accessToken.user.tenant_id
      }
    }
  }
});
if (!project) {
  return res.status(404).json({ error: 'Not found or access denied' });
}

Finally, validate and enforce role-based permissions within business logic or operation hooks. For sensitive operations like deletion or status changes, add checks that verify both project ownership and user role:

Project.observe('before delete', function enforceOwnership(ctx, next) {
  const { currentUser } = ctx.options;
  if (!currentUser) return next(new Error('AUTH_REQUIRED'));
  // Only allow deletion if user is admin or project owner within tenant
  ctx.where = {
    AND: [
      { id: ctx.where.id },
      { tenant_id: currentUser.tenant_id },
      { OR: [{ role: 'admin' }, { ownerId: currentUser.id }] }
    ]
  };
  next();
});

By combining these model-level filters, least-privilege database roles, and explicit authorization checks, you align Loopback endpoints and Cockroachdb permissions to enforce proper access control. middleBrick scans will then show improved findings for Authentication, BOLA/IDOR, and Property Authorization, and the application will correctly enforce multi-tenancy boundaries.