Broken Authentication in Nestjs with Cockroachdb

Broken Authentication in a NestJS application backed by CockroachDB typically arises from a mismatch between application-level session or token handling and the database’s identity and access controls. When authentication logic in NestJS does not properly validate credentials, enforce least privilege, or protect session state, an attacker can bypass or hijack authentication even when CockroachDB is correctly configured.

One common pattern is storing sensitive authentication material or improperly scoped session identifiers in tables without adequate row-level security or column encryption. For example, if a users table in CockroachDB contains columns such as password_hash, password_salt, and is_admin, and the NestJS service retrieves rows with a broad SELECT * FROM users WHERE email = $1 without verifying that the requesting user is authorized to view or modify that row, this can lead to Insecure Direct Object Reference (IDOR) or excessive data exposure. CockroachDB does not inherently enforce application-level authorization; it enforces SQL-level permissions. If the database role used by NestJS has broader privileges than necessary, a compromised service account or an insecurely constructed query can expose or modify other users’ records.

Another vector specific to the NestJS + CockroachDB stack is misconfigured connection pooling or ORM usage that inadvertently leaks credentials or session context. For instance, using the NestJS TypeOrmModule with CockroachDB requires careful handling of connection options. If the connection URL or credentials are stored in environment variables that are not tightly scoped, or if the application reuses a highly privileged database connection across multiple tenants, an attacker who compromises a lower-privilege API endpoint might escalate privileges through the database connection.

Additionally, weak or missing rate limiting on authentication endpoints in NestJS can enable credential stuffing or brute-force attacks against user accounts stored in CockroachDB. Since CockroachDB is strongly consistent and distributed, failed login attempts can be reliably counted and used for adaptive throttling if the application implements this logic. Without it, attackers can repeatedly attempt passwords without triggering account lockout or suspicious activity detection, increasing the likelihood of successful authentication via stolen or guessed credentials.

Finally, improper handling of tokens (such as JWTs) issued by NestJS authentication guards can interact poorly with CockroachDB session stores. If refresh tokens or opaque token identifiers are stored in a CockroachDB table without integrity checks, encrypted storage, or proper revocation mechanisms, an attacker who gains access to the database can forge or reuse tokens. This is particularly risky when token metadata does not include scope, tenant, or binding constraints, allowing lateral movement across users or services.

To remediate authentication issues when using NestJS with CockroachDB, focus on least-privilege database roles, parameterized queries, secure credential storage, and strict session/token handling. Below are concrete examples demonstrating secure patterns.

1. Principle of Least Privilege for CockroachDB Roles

Create a dedicated database role for your NestJS application that has only the permissions needed for its operations. Avoid using a role with superuser or broad table access.

-- In CockroachDB SQL shell
CREATE USER nestjs_app WITH LOGIN PASSWORD 'strong-password-here';
GRANT SELECT, INSERT, UPDATE (email, password_hash, mfa_secret) ON TABLE users TO nestjs_app;
GRANT SELECT ON TABLE public.user_sessions TO nestjs_app;
REVOKE ALL ON DATABASE myapp FROM nestjs_app;

2. Secure Parameterized Query in NestJS with TypeORM

Use repository methods or QueryBuilder with parameters to avoid SQL injection and ensure proper scoping. Never concatenate user input into SQL strings.

import { Injectable } from '@nestjs/common';
import { InjectRepository } from '@nestjs/typeorm';
import { Repository } from 'typeorm';
import { User } from './user.entity';

@Injectable()
export class AuthService {
  constructor(
    @InjectRepository(User)
    private readonly userRepository: Repository,
  ) {}

  async validateUser(email: string, passwordHash: string): Promise {
    return this.userRepository.findOne({
      where: {
        email: email,
        password_hash: passwordHash,
      },
      select: ['id', 'email', 'password_hash', 'mfa_secret'],
    });
  }
}

3. Encrypt and Isolate Sensitive Columns

Store passwords and MFA secrets using strong, adaptive hashing (e.g., argon2id) in NestJS before writing to CockroachDB. Do not store plaintext or weakly hashed values.

import { compareSync, hashSync } from 'bcryptjs';

const plainPassword = 'userPassword123';
const hashedPassword = hashSync(plainPassword, 12);

// Store hashedPassword in the password_hash column
// Verify during login
const isValid = compareSync(enteredPassword, storedHash);

4. Use Short-Lived Access Tokens and Secure Refresh Token Storage

Issue short-lived JWTs for API access and store refresh tokens as opaque identifiers in a CockroachDB table with strict ownership checks.

// Example token payload
const accessToken = jwt.sign(
  { sub: user.id, scope: 'api:read api:write', tenant: 'acme' },
  process.env.JWT_SECRET,
  { expiresIn: '15m' },
);

// Store refresh token metadata securely
await this.refreshTokenRepository.insert({
  token_id: uuidv4(),
  user_id: user.id,
  expires_at: new Date(Date.now() + 7 * 24 * 60 * 60 * 1000),
  revoked: false,
});

5. Enforce Row-Level Security in Application Logic

Always scope queries by tenant or user ID, even if database roles restrict access. This prevents IDOR if roles are misconfigured later.

async findSessionsForUser(userId: string, requestingUserId: string) {
  if (userId !== requestingUserId) {
    throw new ForbiddenException('Cannot view other users sessions');
  }
  return this.sessionRepository.findBy({ user_id: userId });
}