Need

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

Context

• Usage of PHP 7.0 for server-side scripting and web development
• Usage of Illuminate\\Http\\Request for handling HTTP requests in Laravel
• Usage of App\\PromotionCode for managing and applying promotion codes
• Usage of a Controller for handling request and response logic in a Node.js application

Description

Non compliant code

        input('code');
        $promotionCode = PromotionCode::where('code', $code)->first();

        if ($promotionCode) {
            return response()->json(['message' => 'Promotion code is valid.']);
        } else {
            return response()->json(['message' => 'Promotion code is not valid.']);
        }
    }
}

        
        

In this PHP Laravel code snippet, we have a PromotionCodeController with a method checkPromotionCode. This method receives a HTTP request and retrieves a promotion code from the request input. It then checks if the promotion code exists in the database by using Laravel's Eloquent ORM to query the PromotionCode model.

The vulnerability here is that there is no protection against brute force attacks. An attacker can keep sending HTTP requests with different promotion codes until they find a valid one. There are no measures in place to limit the number of attempts, delay responses after failed attempts, or block an IP address after a certain number of failed attempts. This makes the application susceptible to automated attacks to guess valid promotion codes.

Steps

• Implement a rate limiting mechanism to limit the number of requests a user can make within a certain time period.
• Use a CAPTCHA to prevent automated scripts from making requests.
• Implement account lockout policies after a certain number of failed attempts.
• Use a delay mechanism to slow down the rate of requests after a certain number of failed attempts.
• Consider using a more secure method for generating and validating promotion codes, such as using a cryptographic hash function.

Compliant code

        input('code');
        $ip = $request->ip();

        if (RateLimiter::tooManyAttempts($ip, 5, 1)) {
            return response()->json(['message' => 'Too many attempts. Please try again later.']);
        }

        $promotionCode = PromotionCode::where('code', $code)->first();

        if ($promotionCode) {
            RateLimiter::clear($ip);
            return response()->json(['message' => 'Promotion code is valid.']);
        } else {
            RateLimiter::hit($ip);
            return response()->json(['message' => 'Promotion code is not valid.']);
        }
    }
}
        
        

The updated code now includes a rate limiting mechanism that limits the number of requests a user can make within a certain time period. This is done using Laravel's built-in RateLimiter facade.

The RateLimiter::tooManyAttempts($ip, 5, 1) method checks if the user has made too many attempts. In this case, the limit is set to 5 attempts per minute. If the user exceeds this limit, they will receive a response indicating that they have made too many attempts and should try again later.

When a user submits a valid promotion code, the RateLimiter::clear($ip) method is called to clear the rate limit for that user. This allows the user to continue making requests without being limited.

If the user submits an invalid promotion code, the RateLimiter::hit($ip) method is called to increment the number of attempts made by the user. This will count towards the rate limit.

This solution helps to protect against brute force attacks by limiting the number of requests a user can make within a certain time period. However, it is recommended to also implement other security measures such as CAPTCHA, account lockout policies, delay mechanisms, and secure methods for generating and validating promotion codes.

References

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