Broken Access Control in Aspnet with Cockroachdb

Broken Access Control occurs when an API fails to enforce proper authorization checks, allowing one user to access or modify another user's resources. In an Aspnet application using Cockroachdb as the backend, the risk is amplified when authorization logic is applied at the application layer but not consistently enforced by the database, or when row-level security (RLS) is not leveraged. Cockroachdb supports PostgreSQL wire protocol and offers native features such as RLS and row filters, but if these are not explicitly configured in the Aspnet data access layer, the application may rely solely on in-code checks that can be bypassed.

For example, consider an Aspnet Web API that retrieves user profiles via a route like /api/users/{id}. If the endpoint queries Cockroachdb using a simple SQL string such as SELECT * FROM users WHERE id = @id without validating that the authenticated user has permission to view the requested id, an attacker can modify the id parameter to access other users' data. This is a classic BOLA (Broken Object Level Authorization) pattern, which is among the OWASP API Top 10 and commonly observed in APIs scanned by middleBrick.

When using Cockroachdb, additional risk arises if the database connection uses a highly privileged account from Aspnet configuration. If an attacker exploits a missing authorization check and injects a malicious query, they might leverage SQL features available in Cockroachdb—such as secondary indexes or schema introspection—to enumerate users or extract metadata. Because Cockroachdb is a distributed SQL database, it can scale horizontally; however, without proper tenant isolation via row-level security or application-level tenant scoping, a single compromised query could expose multiple tenants' data across nodes.

middleBrick identifies Broken Access Control through its BOLA/IDOR and Property Authorization checks, which analyze unauthenticated attack surfaces and detect whether endpoints enforce ownership or tenant scoping. In Aspnet apps backed by Cockroachdb, findings often reveal missing [Authorize] attributes, incomplete policy evaluation, or lack of consistent data filtering. Even when Aspnet Core Identity is used for authentication, authorization must be explicitly enforced at the data access layer to ensure that every Cockroachdb query includes a tenant or user context that matches the authenticated subject.

To mitigate this specific combination, developers should treat the database as a trust boundary. Authorization checks in Aspnet should not only guard HTTP endpoints but also be embedded in data access patterns that construct Cockroachdb queries. This means using parameterized queries with user context, applying filters that restrict rows by authenticated user ID or tenant ID, and validating that the resulting rowset is non-empty and owned by the requester. middleBrick’s LLM/AI Security checks can further validate that system prompts and generated outputs do not leak user context or internal schema details when debugging such flows.

Remediation requires integrating authorization into every database interaction. In Aspnet, this means using dependency-injected services that construct Cockroachdb queries with explicit tenant or user filters. Below are concrete, realistic code examples using Npgsql with Cockroachdb, demonstrating how to enforce row-level scoping and avoid BOLA.

1. Parameterized query with user context

Always include the authenticated user ID in the WHERE clause. Do not rely on route or query parameters alone.

// Example using Npgsql in an Aspnet Core service
public async Task<UserProfile> GetUserProfileAsync(Guid userId, Guid requesterId)
{
    await using var conn = new NpgsqlConnection(_connectionString);
    await conn.OpenAsync();

    const string sql = @"
        SELECT id, username, email, tenant_id
        FROM user_profiles
        WHERE id = @userId AND tenant_id = (SELECT tenant_id FROM user_profiles WHERE id = @requesterId)
        LIMIT 1";

    await using var cmd = new NpgsqlCommand(sql, conn);
    cmd.Parameters.AddWithValue("@userId", userId);
    cmd.Parameters.AddWithValue("@requesterId", requesterId);

    await using var reader = await cmd.ExecuteReaderAsync();
    if (!await reader.ReadAsync())
    {
        return null; // Not found or no permission
    }

    return new UserProfile
    {
        Id = reader.GetGuid(reader.GetOrdinal("id")),
        Username = reader.GetString(reader.GetOrdinal("username")),
        Email = reader.GetString(reader.GetOrdinal("email")),
        TenantId = reader.GetGuid(reader.GetOrdinal("tenant_id"))
    };
}

2. Enforcing tenant isolation via row filters

If your Cockroachdb schema includes a tenant_id column, use it in every query. Aspnet policies can inject the tenant context from claims.

public async Task<IEnumerable<Order>> ListOrdersForTenantAsync(Guid tenantId)
{
    await using var conn = new NpgsqlConnection(_connectionString);
    await conn.OpenAsync();

    const string sql = @"
        SELECT order_id, total, currency
        FROM orders
        WHERE tenant_id = @tenantId
        ORDER BY created_at DESC";

    await using var cmd = new NpgsqlCommand(sql, conn);
    cmd.Parameters.AddWithValue("@tenantId", tenantId);

    await using var reader = await cmd.ExecuteReaderAsync();
    var orders = new List<Order>();
    while (await reader.ReadAsync())
    {
        orders.Add(new Order
        {
            OrderId = reader.GetGuid(reader.GetOrdinal("order_id")),
            Total = reader.GetDecimal(reader.GetOrdinal("total")),
            Currency = reader.GetString(reader.GetOrdinal("currency"))
        });
    }
    return orders;
}

3. Using database roles and prepared statements

For enhanced security, use Cockroachdb’s prepared statements and restrict the application database user to least privilege. In Aspnet, configure the connection string to use a role that cannot read or write across tenants.

-- Cockroachdb SQL to create a restricted role (run once via admin tooling)
CREATE ROLE aspnet_app;
GRANT SELECT, INSERT, UPDATE ON user_profiles TO aspnet_app;
-- Explicitly deny cross-tenant access by not granting broader permissions

-- Example prepared statement usage in Aspnet
await using var conn = new NpgsqlConnection(_connectionString);
await conn.OpenAsync();
await using var cmd = new NpgsqlCommand("EXECUTE get_user_for_tenant($1, $2)", conn);
cmd.Parameters.AddWithValue("userId", userId);
cmd.Parameters.AddWithValue("requesterId", requesterId);

4. Validating with middleware

In Aspnet Core, add a simple authorization filter that ensures the requester can access the target resource before the controller executes.

public class TenantAuthorizationFilter : IAsyncActionFilter
{
    public async Task OnActionExecutionAsync(ActionExecutingContext context, ActionExecutionDelegate next)
    {
        if (context.ActionArguments.TryGetValue("id", out var id)
            && context.HttpContext.User.FindFirst("tenant_id"?.ToString()) is { } tenantClaim)
        {
            var tenantId = Guid.Parse(tenantClaim.Value);
            // Optionally validate ownership via a lightweight service call
            var isValid = await ValidateOwnershipAsync(id, tenantId);
            if (!isValid)
            {
                context.Result = new ForbidResult();
                return;
            }
        }
        await next();
    }
}

By combining these patterns—parameterized queries, tenant-aware SQL, least-privilege database roles, and Aspnet middleware—you reduce the attack surface for Broken Access Control. middleBrick’s scans can verify that such controls are present and that no unauthenticated endpoints expose raw identifiers without proper scoping.