IDS/IPS Solution for Web Applications

When designing an intrusion detection prevention (IDS/IPS) solution for a customer's web application in a single VPC, there are various options to consider.

Option A: Implement IDS/IPS agents on each instance running in the VPC. This option involves installing IDS/IPS agents on each instance running in the VPC. This would require installing the agents on all instances, which can be time-consuming and labor-intensive. Additionally, the approach will not protect traffic coming into the VPC and traffic within the VPC.

Option B: Configure an instance in each subnet to switch its network interface card to promiscuous mode and analyze network traffic. This option requires configuring a dedicated instance in each subnet to switch its network interface card to promiscuous mode, allowing it to capture all network traffic within that subnet. However, it can be difficult to scale and manage, and it will not provide protection against traffic entering the VPC.

Option C: Implement Elastic Load Balancing with SSL listeners in front of the web applications. This option involves implementing Elastic Load Balancing (ELB) with SSL listeners in front of the web applications. This provides load balancing and SSL offloading, ensuring that traffic coming into the VPC is secure. However, ELB does not provide IDS/IPS functionality, so additional measures would be required to provide intrusion detection and prevention.

Option D: Implement a reverse proxy layer in front of web servers and configure IDS/IPS agents on each reverse proxy server. This option involves implementing a reverse proxy layer in front of the web servers, with IDS/IPS agents installed on each reverse proxy server. This provides a layer of protection for traffic coming into the VPC and traffic within the VPC. However, it can be complex to manage, and additional measures may be required to provide load balancing and SSL offloading.

Overall, option D is the best choice because it provides protection for both incoming and internal traffic, while also allowing for load balancing and SSL offloading. Additionally, implementing a reverse proxy layer can provide additional benefits such as caching and content delivery. However, it is important to carefully consider the management overhead and potential complexity involved in this option.