Need

Implementation of strong authentication mechanisms to prevent brute force attacks on promotional codes.

Context

• Usage of Scala for building scalable and high-performance applications
• Usage of play.api.mvc for handling HTTP requests and responses in Play Framework
• Usage of Scala's global execution context for managing concurrent and asynchronous operations

Description

Non compliant code

        import play.api.mvc._
import scala.concurrent.ExecutionContext.Implicits.global

class PromoCodeController @Inject()(cc: ControllerComponents) extends AbstractController(cc) {

  def validatePromoCode(promoCode: String) = Action.async { implicit request: Request[AnyContent] =>
    
    // Assume we have a method that checks if the promo code is valid
    if (isPromoCodeValid(promoCode)) {
      Future.successful(Ok("Promo code is valid."))
    } else {
      Future.successful(BadRequest("Invalid promo code."))
    }
  }

  def isPromoCodeValid(promoCode: String): Boolean = {
    // Check the promo code against the database
    // This is a placeholder for the actual implementation
    false
  }
}
        
        

This Scala code using the Play framework presents a web server with an endpoint to validate promotional codes. The validatePromoCode method in the PromoCodeController class takes a promotional code as input and checks if it is valid using the isPromoCodeValid method.

The vulnerability lies in the fact that there is no protection against brute force attacks. An attacker can potentially make an unlimited number of requests to the validatePromoCode endpoint with different promotional codes until they find a valid one.

There are no mechanisms in place to limit the number of requests a client can make in a certain time period. This lack of rate limiting makes the application susceptible to automated attacks, where an attacker uses a script to generate and try a large number of promotional codes.

Additionally, there are no mechanisms in place to monitor and alert on suspicious activity, such as a large number of failed validation attempts in a short period of time, which could indicate a brute force attack.

Steps

• Implement rate limiting to limit the number of requests per IP address or user.
• Implement account lockout mechanism to temporarily lock an account after multiple failed login attempts.
• Implement CAPTCHA or reCAPTCHA to differentiate between human and automated requests.
• Implement strong and complex promo code generation algorithm to make it difficult to guess valid promo codes.
• Implement logging and monitoring to detect and respond to brute force attacks.
• Regularly update and patch the application and its dependencies to fix any security vulnerabilities.

Compliant code

        import play.api.mvc._
import scala.concurrent.ExecutionContext.Implicits.global
import play.filters.headers.SecurityHeadersFilter
import play.api.mvc.Security.AuthenticatedBuilder
import play.api.mvc.Security.AuthenticatedRequest

class PromoCodeController @Inject()(cc: ControllerComponents, rateLimiter: RateLimiter) extends AbstractController(cc) {

  def validatePromoCode(promoCode: String) = Action.async { implicit request: Request[AnyContent] =>
    
    // Check if the IP address has exceeded the rate limit
    if (rateLimiter.isRateLimitExceeded(request.remoteAddress)) {
      Future.successful(TooManyRequest("Too many requests. Please try again later."))
    } else {
      // Assume we have a method that checks if the promo code is valid
      if (isPromoCodeValid(promoCode)) {
        Future.successful(Ok("Promo code is valid."))
      } else {
        Future.successful(BadRequest("Invalid promo code."))
      }
    }
  }

  def isPromoCodeValid(promoCode: String): Boolean = {
    // Check the promo code against the database
    // This is a placeholder for the actual implementation
    false
  }
}
        
        

The updated code includes a rate limiter to protect against brute force attacks. The rate limiter checks if the IP address has exceeded the maximum number of requests allowed within a certain time period. If the rate limit is exceeded, the server responds with a TooManyRequest status code and a message asking the user to try again later.

This solution also assumes the existence of a RateLimiter class or service that provides the isRateLimitExceeded method. This service should be implemented to track the number of requests from each IP address and determine if the rate limit has been exceeded.

Please note that this is a basic implementation and may need to be adjusted based on your specific requirements and environment. For example, you might want to implement more sophisticated rate limiting strategies, such as gradually reducing the rate limit for IP addresses that repeatedly exceed the limit.

In addition to rate limiting, other measures should be taken to protect against brute force attacks, such as implementing CAPTCHA or reCAPTCHA, using strong and complex promo code generation algorithms, and regularly updating and patching the application and its dependencies.

References

• 330. Lack of protection against brute force attacks - Credentials