Identification Failures in Fastapi with Cockroachdb

Identification failures occur when an API fails to properly enforce identification checks across the request lifecycle, allowing attackers to access or manipulate resources that belong to other users. This is commonly categorized as Broken Object Level Authorization (BOLA), also known as Insecure Direct Object References (IDOR). The combination of FastAPI and CockroachDB can inadvertently expose identification failures when application-level identifiers (e.g., tenant_id, org_id, user_id) are used to construct database queries but are not consistently validated against the authenticated subject’s permissions.

In FastAPI, route parameters and query parameters are often bound directly to path or query inputs. If these inputs are used to form CockroachDB SQL statements without verifying that the requesting identity is authorized for the referenced object, the API exposes a BOLA surface. For example, an endpoint like /orgs/{org_id}/settings might extract org_id from the path and use it in a CockroachDB query such as SELECT * FROM settings WHERE org_id = $1. If the endpoint relies solely on the path parameter and does not confirm that the authenticated principal is a member of that org, an attacker can enumerate org IDs and read or modify another organization’s settings.

CockroachDB’s SQL compatibility with PostgreSQL drivers means typical Python database libraries (e.g., asyncpg or SQLAlchemy with appropriate drivers) are used. However, the database itself does not enforce application-level identity checks; it enforces schema-level constraints and access control at the role/connection level. Therefore, identification checks must be implemented in the API layer. A common anti-pattern is to construct dynamic SQL by string interpolation, which not only introduces SQL injection risk but also obscures authorization boundaries, making identification failures harder to audit.

Another contributing factor is missing or inconsistent tenant/context propagation. In multi-tenant designs, the tenant or organization context should be verified on each request and applied as a filter on every CockroachDB query. If the FastAPI dependency that injects the database connection or session does not include the tenant filter, or if the filter is omitted in certain routes, an attacker can leverage unauthenticated endpoints or weak access controls to traverse relationships (e.g., org → projects → secrets) without proper identification checks.

Additionally, insecure default behaviors or missing validation on identifiers can lead to IDOR when UUIDs or numeric IDs are predictable. Even with CockroachDB’s strong consistency, the API must ensure that every read and write is scoped by the authenticated subject’s allowed set. Without explicit checks, an attacker can modify URLs or parameters to reference other rows and observe whether the API enforces identification boundaries, which is exactly what middleBrick’s BOLA/IDOR checks validate during a scan.

Remediation centers on enforcing identification checks before constructing and executing CockroachDB queries. Always resolve the authenticated subject (user or service) and validate that the requested resource is associated with that subject. Use parameterized queries to prevent injection and keep authorization logic explicit.

Example secure FastAPI route with asyncpg and CockroachDB:

from fastapi import Depends, HTTPException, status
from fastapi.security import HTTPBearer
import asyncpg

security = HTTPBearer()

async def get_db_pool():
    # Assume this returns a pool configured for CockroachDB
    # In practice, manage lifecycle with FastAPI dependencies
    pass

async def get_current_tenant_subject(token: str = Depends(security)):
    # Validate token, extract subject and tenant context
    # Return a dict with tenant_id and user_id
    return {"tenant_id": "acme-tenant", "user_id": "u-123"}

async def get_db_connection():
    pool = await get_db_pool()
    conn = await pool.acquire()
    return conn

@app.get("/orgs/{org_id}/settings")
async def read_org_settings(
    org_id: str,
    subject: dict = Depends(get_current_tenant_subject),
    conn: asyncpg.Connection = Depends(get_db_connection)
):
    # Critical: verify that the subject is a member of org_id
    row = await conn.fetchrow(
        "SELECT org_id FROM org_memberships WHERE org_id = $1 AND user_id = $2",
        org_id,
        subject["user_id"]
    )
    if row is None:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="Access denied")
    # Safe query: subject is confirmed as a member
    settings = await conn.fetchrow(
        "SELECT key, value FROM org_settings WHERE org_id = $1",
        org_id
    )
    await pool.release(conn)
    return settings

Key points in the example:

• The subject is resolved via dependency injection and includes tenant and user context.
• Authorization is checked explicitly by querying an access table (org_memberships) before accessing org-specific data.
• All CockroachDB interactions use parameterized queries ($1, $2), avoiding injection and keeping the query plan stable.
• The connection is released back to the pool after the operation, maintaining safe resource handling.

For SQLAlchemy with CockroachDB, apply the same principle at the query level:

from sqlalchemy.orm import Session
from fastapi import Depends, HTTPException, status

# Assume engine or session_factory is configured for CockroachDB
# and that TenantContext includes tenant_id and user_id
def get_tenant_context():
    return {"tenant_id": "acme-tenant", "user_id": "u-123"}

@app.get("/projects/{project_id}")
async def read_project(
    project_id: int,
    context: dict = Depends(get_tenant_context),
    db: Session = Depends(get_db_session)
):
    # Verify membership before accessing project data
    membership = db.query(ProjectMembership).filter(
        ProjectMembership.project_id == project_id,
        ProjectMembership.user_id == context["user_id"]
    ).first()
    if not membership:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="Forbidden")
    project = db.query(Project).filter(Project.id == project_id).first()
    if project is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Not found")
    return project

Additional remediation guidance:

• Apply tenant or org filters on every CockroachDB query in multi-tenant scenarios; do not rely on row-level security alone for identification checks.
• Validate identifiers against an access relationship table rather than trusting path parameters alone.
• Use dependency injection to propagate identity and tenant context consistently across routes.
• Combine these practices with middleBrick’s BOLA/IDOR checks to verify that your API correctly enforces identification boundaries across authenticated and unauthenticated attack surfaces.