Brute Force Attack in Nestjs with Cockroachdb

A brute force attack against a NestJS application backed by CockroachDB typically targets authentication endpoints where credentials are verified. Because CockroachDB is a distributed SQL database, it can serve high request rates with strong consistency, which may allow an attacker to perform many rapid login attempts before account lockout or rate limiting takes effect. If the NestJS service does not enforce per-user or per-IP rate limits and does not use constant-time comparison for credentials, an attacker can iteratively submit passwords or use credential spraying to identify valid accounts.

In this stack, the attack surface includes the API layer (HTTP requests hitting NestJS controllers), the service layer (NestJS providers that query CockroachDB), and the database layer (SQL queries executed against CockroachDB). A common vulnerability pattern is constructing dynamic SQL or using an ORM in a way that does not properly parameterize queries, which can lead to injection that aids enumeration. However, even with parameterized queries, an attacker can exhaust authentication attempts if the application does not implement throttling, account lockout with increasing delays, or captchas after repeated failures. CockroachDB’s scalability can inadvertently support high request concurrency, making it easier for an attacker to send many parallel requests without experiencing the delays that a single-node database might impose.

The use of OpenAPI specs in middleBrick changes how findings are mapped: authentication weaknesses and BOLA/IDOR checks can reveal whether login endpoints lack multi-factor options, expose verbose error messages that distinguish between missing users and incorrect passwords, or allow password reset tokens to be enumerated. When an OpenAPI specification is analyzed, paths such as POST /auth/login can be checked for expected security schemes and for whether request bodies reference models that omit brute force protections like maxAttempts or lockoutWindow. Runtime probes then validate whether the implementation aligns with the spec, ensuring that protections such as rate limiting and secure password comparison are enforced in practice, not just documented.

Remediation focuses on reducing the effectiveness of brute force attempts and ensuring database interactions do not leak information. In NestJS, implement a rate-limiting guard that applies per user identifier and per IP address before the authentication logic reaches the database. Use a sliding window or token bucket algorithm stored in a fast key-value store (not the database) to track attempt counts, and enforce increasing delays or temporary lockouts after a threshold is crossed. Ensure that error responses for authentication failures are uniform and do not reveal whether a username exists, which prevents attackers from enumerating valid accounts.

When querying CockroachDB from NestJS, use parameterized queries via an ORM or query builder to avoid injection and to ensure consistent handling of inputs. Below is a concrete example using the pg driver with TypeORM configured for CockroachDB, showing a parameterized login check that avoids timing leaks by using a dummy hash when the user is not found:

import { Injectable } from '@nestjs/common';
import { InjectRepository } from '@nestjs/typeorm';
import { Repository } from 'typeorm';
import { User } from './user.entity';
import * as argon2 from 'argon2';

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

  async validateUser(username: string, password: string): Promise {
    // Use parameterized query via repository to avoid SQL injection
    const user = await this.userRepository.findOne({
      where: { username },
    });

    // Use constant-time comparison by hashing the provided password against the stored hash
    const candidate = user ? user.passwordHash : await argon2.hash('dummy');
    const verified = await argon2.verify(candidate, password);

    // Return user only if verified; otherwise return null to avoid leaking existence
    return verified ? user : null;
  }
}

Additionally, enforce schema-level protections in CockroachDB by setting password hash columns to NOT NULL and using strong collation settings to avoid case-insensitive bypasses. Combine this with application-level controls such as MFA for privileged accounts and monitoring for repeated failures against the same user or IP. middleBrick’s authentication and BOLA/IDOR checks can validate that these protections are reflected in your OpenAPI spec and confirmed at runtime, ensuring that brute force risks are addressed across the stack.