Cross Site Request Forgery in Flask with Cockroachdb

Cross Site Request Forgery (CSRF) in a Flask application that uses CockroachDB arises from the interaction between Flask’s request handling and how database operations are triggered. Flask does not enforce CSRF protection by default, and if routes rely solely on cookies for session identity without anti-CSRF tokens, an attacker can craft malicious web pages that cause a victim’s browser to issue unintended authenticated requests. When those requests reach Flask endpoints that perform database writes or state changes on CockroachDB, the operations execute in the context of the victim’s permissions, potentially modifying or retrieving data stored in CockroachDB.

With CockroachDB, which provides a PostgreSQL-compatible wire protocol, common patterns such as using psycopg or SQLAlchemy with a CockroachDB connection string can inadvertently encourage insecure coding practices if developers assume database-level constraints alone prevent unsafe operations. For example, a Flask route that updates a user’s email via a GET request or accepts unvalidated parameters that are directly interpolated into SQL increases risk. Even when using an ORM, missing checks on the origin of the request and missing per-action authorization can expose dangerous endpoints. An attacker may trick a user into visiting a page that calls /transfer or /email/update, causing the backend to execute SQL like UPDATE accounts SET email = '[email protected]' WHERE user_id = $1 on CockroachDB, altering data without user consent.

The risk is amplified when session management relies only on cookies and lacks SameSite attributes or CSRF tokens. CockroachDB’s strong consistency does not protect against logical flaws in the application layer; if Flask endpoints do not verify intent, statements sent to CockroachDB will be executed as long as authentication cookies are present. Additionally, verbose error messages returned from CockroachDB can aid attackers in refining requests, making it important to ensure that error handling does not leak database schema details. Therefore, CSRF protection for Flask apps using CockroachDB must focus on request validation, origin checks, and secure session handling rather than assuming database features mitigate application-level CSRF.

Remediation centers on ensuring every state-changing request is intentional and authenticated with proper anti-CSRF controls. Use Flask-WTF or a similar library to generate and validate CSRF tokens for all mutating methods (POST, PUT, DELETE). Combine this with strict CORS policies and the SameSite attribute on cookies. For database interactions with CockroachDB, prefer parameterized queries or an ORM to avoid injection and ensure values are correctly passed. Below are concrete code examples demonstrating secure patterns.

Secure Flask route with CSRF protection and CockroachDB (psycopg) example

from flask import Flask, request, jsonify, session
from flask_wtf.csrf import CSRFProtect, generate_csrf
import psycopg

app = Flask(__name__)
app.config['SECRET_KEY'] = 'your-secret-key'
csrf = CSRFProtect(app)

# CockroachDB connection helper
def get_db():
    return psycopg.connect(
        dsn="postgresql://user:password@host:26257/dbname?sslmode=require",
        # CockroachDB-specific options can be added here
    )

@app.route('/api/email', methods=['POST'])
def update_email():
    # CSRF token is validated automatically by Flask-WTF for non-GET requests
    user_id = session.get('user_id')
    if user_id is None:
        return jsonify({'error': 'unauthorized'}), 401
    data = request.get_json()
    new_email = data.get('email')
    if not new_email or '@' not in new_email:
        return jsonify({'error': 'invalid email'}), 400
    try:
        with get_db() as conn:
            with conn.cursor() as cur:
                cur.execute(
                    'UPDATE users SET email = $1 WHERE id = $2',
                    (new_email, user_id)
                )
        return jsonify({'status': 'ok'})
    except Exception as e:
        app.logger.error(f'Database error: {e}')
        return jsonify({'error': 'internal server error'}), 500

@app.route('/api/csrf-token', methods=['GET'])
def csrf_token():
    return jsonify({'csrfToken': generate_csrf()})

Secure Flask route with SQLAlchemy and CockroachDB

from flask import Flask, request, session, jsonify
from flask_sqlalchemy import SQLAlchemy
from sqlalchemy import text

app = Flask(__name__)
app.config['SECRET_KEY'] = 'your-secret-key'
app.config['SQLALCHEMY_DATABASE_URI'] = 'cockroachdb://user:password@host:26257/dbname?sslmode=require'
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
db = SQLAlchemy(app)

class User(db.Model):
    __tablename__ = 'users'
    id = db.Column(db.Integer, primary_key=True)
    email = db.Column(db.String, nullable=False)

@app.route('/api/update-email', methods=['POST'])
def secure_update_email():
    if 'user_id' not in session:
        return jsonify({'error': 'unauthorized'}), 401
    data = request.get_json()
    new_email = data.get('email')
    if not new_email or '@' not in new_email:
        return jsonify({'error': 'invalid email'}), 400
    try:
        # Use parameterized queries via SQLAlchemy to avoid injection
        stmt = text('UPDATE users SET email = :email WHERE id = :user_id')
        db.session.execute(stmt, {'email': new_email, 'user_id': session['user_id']})
        db.session.commit()
        return jsonify({'status': 'ok'})
    except Exception as e:
        db.session.rollback()
        app.logger.error(f'Database error: {e}')
        return jsonify({'error': 'internal server error'}), 500

In both examples, ensure cookies include SameSite=Lax or Strict and that sensitive routes validate the Origin or Referer header where appropriate. Use the middleBrick CLI (middlebrick scan <url>) or GitHub Action to verify that CSRF protections are correctly detected and that no unsafe routes remain. The Pro plan can enable continuous monitoring to catch regressions, while the MCP Server allows scanning APIs directly from your AI coding assistant during development.