Question

Difficulty: EasyNetwork and Infrastructure Security

A company is configuring a Virtual Private Cloud (VPC) to host a new application. The security administrator wants to implement a defense-in-depth strategy by combining instance-level firewall protection with subnet-level firewall protection. Which of the following statements correctly describe the characteristics of Security Groups and Network Access Control Lists (Network ACLs)? (Select TWO.)

  1. A
    Security Groups are stateless firewalls that operate at the subnet level.
  2. B
    Network ACLs are stateful firewalls that operate at the instance level.
  3. Security Groups are stateful firewalls that control traffic at the instance level.Answer
  4. Network ACLs are stateless firewalls that control traffic at the subnet level.Answer
  5. E
    AWS is responsible for configuring all Security Group and Network ACL rules on behalf of the customer.

Answer

The correct answers are the statements that state Security Groups are stateful firewalls operating at the instance level, and Network ACLs are stateless firewalls operating at the subnet level.
Security Groups act as a firewall for associated Amazon EC2 instances, controlling both inbound and outbound traffic at the instance level. They are stateful, meaning any allowed inbound traffic is automatically allowed to exit. Network ACLs act as a firewall for associated subnets, controlling traffic entering and leaving the subnet. They are stateless, meaning return traffic must be explicitly allowed by a corresponding rule.

Step-by-Step Solution

1
Analyze the configuration and characteristics of Security Groups.
Identify that Security Groups are applied at the instance level (e.g., to elastic network interfaces) and are stateful.
This helps verify the correct statements regarding Security Groups.
2
Analyze the configuration and characteristics of Network ACLs.
Identify that Network ACLs are applied at the subnet boundary and are stateless.
This helps verify the correct statements regarding Network ACLs.
3
Review the Shared Responsibility Model regarding firewall rule configuration.
Confirm that configuring security rules is a customer responsibility, ruling out options that shift this responsibility to AWS.
This eliminates incorrect distractors regarding operational responsibilities.

Key Concept

Stateful Security Groups vs. Stateless Network ACLs
Estimated Time:1m 0s
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