SAA-C03 Design Secure Architectures Practice Test 9 — 15 Questions

Question 1

A central security account stores encrypted log files in S3 using a customer managed AWS KMS key. A partner account already has S3 bucket access through an assumed role and now must also be able to encrypt and decrypt objects that use the same KMS key. Which two actions are required? Select two.

Accepted Answer

Update the KMS key policy to allow the partner role or account to use the key.. Option A is correct because the KMS key policy must explicitly grant the partner account or role permission to use the key for cryptographic operations. Without this cross-account policy statement, the key remains inaccessible to the partner account, even if the partner has S3 bucket access. This is a fundamental requirement for cross-account KMS key usage.

Answer

Enable automatic key rotation to solve the cross-account access requirement.

Answer

Replace the CMK with the AWS managed key alias/aws/s3.

Answer

Export the KMS key material and share it with the partner account.

Question 2

Based on the exhibit, the platform team wants developers to create application roles for Lambda and ECS, but no developer-created role may ever exceed the approved permission set. Which change best meets this requirement?

Accepted Answer

Attach a permissions boundary strategy to the delegated workflow and require every created role to include that boundary using the iam:PermissionsBoundary condition.. Option B is correct because it uses an IAM permissions boundary attached to the delegated role creation workflow, combined with the `iam:PermissionsBoundary` condition key to enforce that every developer-created role must include that boundary. This ensures no role can exceed the approved permission set, as the boundary acts as a maximum limit on permissions, even if the role's policy grants more. The delegated workflow (e.g., AWS Service Catalog or IAM Role creation via Lambda) can create roles, but the boundary prevents any escalation beyond the predefined scope.

Answer

Remove all IAM permissions from AppProvisioner and require a central security team to create every role manually.

Answer

Allow developers to keep creating roles, but add a CloudTrail rule that alerts security after a privileged policy is attached.

Answer

Move the delegated IAM workflow into a separate VPC and restrict it with security groups and network ACLs.

Question 3

Based on the exhibit, the company has one shared S3 bucket for many internal teams. Security wants each team to access only its own prefix, ACLs must remain disabled, and the current bucket policy has become too large and error-prone. What is the best redesign?

Accepted Answer

Create one S3 access point per team and attach an access point policy that limits that team to its own prefix.. Option C is correct because S3 Access Points allow you to create separate access points for each team, each with its own policy that restricts access to a specific prefix (e.g., s3://shared-bucket/team-a/). This eliminates the need for a large, error-prone bucket policy while keeping ACLs disabled, as access is managed through IAM policies and access point policies. It also maintains a single shared bucket, simplifying management and cost allocation.

Answer

Re-enable object ACLs and manage access by setting object-level ACLs for each team's prefix.

Answer

Split the bucket into one bucket per team and keep using a single shared bucket policy for all of them.

Answer

Make the bucket public and issue presigned URLs for team access so IAM policies are no longer needed.

Question 4

A workload runs in private subnets and must reach Amazon S3 and AWS Secrets Manager without using the internet or a NAT gateway. The team wants to keep the traffic on AWS private networking and avoid public IPs. Which two changes should the architect make? Select two.

Accepted Answer

Create an S3 gateway VPC endpoint and update the route tables for the private subnets.. Option A is correct because an S3 gateway VPC endpoint enables private subnet instances to access S3 over the AWS network without requiring internet gateways or NAT gateways. Gateway endpoints use route table entries to direct S3 traffic through the AWS backbone, avoiding public IPs entirely.

Answer

Place a NAT gateway in the public subnet so the private instances can reach AWS services.

Answer

Assign public IPv4 addresses to the instances and restrict them with security groups.

Answer

Use VPC peering to the AWS service endpoints instead of VPC endpoints.

Question 5

An administrator needs the ability to read and update infrastructure for a specific AWS account, but only when using MFA. The security team wants to eliminate long-lived administrator access keys and ensure that even if someone obtains temporary session credentials, actions are only allowed with MFA present.

Which IAM design best meets these requirements?

Accepted Answer

Create an IAM role for administration and use a permissions policy that allows only the required read/write actions. Add a condition to deny all allowed actions unless aws:MultiFactorAuthPresent is true.. Option B is correct because it uses an IAM role with a permissions policy that includes a condition key `aws:MultiFactorAuthPresent` set to `true`. This ensures that any API call made using temporary credentials from the role requires MFA to be present, eliminating long-lived access keys and enforcing MFA for every action. The role-based approach also aligns with the principle of least privilege by scoping actions to only required read/write operations.

Answer

Create an IAM user for administrators with AdministratorAccess and require MFA only at the IAM user login.

Answer

Attach policies to an IAM user that allow read/write actions and enable MFA in the account, but do not use condition keys in IAM policies.

Answer

Use a role with the correct actions but enforce MFA only in the application by prompting users for an OTP before every API call.

Question 6

Based on the exhibit, a workload in private subnets must reach only Amazon S3 and AWS Secrets Manager. The team wants to eliminate internet exposure for those calls and reduce NAT gateway charges. What change should be made?

Accepted Answer

Create an S3 gateway endpoint and a Secrets Manager interface endpoint with private DNS, then remove NAT dependency for those service calls.. Option C is correct because VPC Gateway Endpoints for S3 and VPC Interface Endpoints for Secrets Manager allow private subnet instances to access these services over the AWS network without traversing the internet or a NAT gateway. Enabling private DNS on the interface endpoint ensures that standard DNS names resolve to private IPs, eliminating the need for NAT and reducing costs.

Answer

Move the instances into a public subnet and restrict inbound access with security groups.

Answer

Add a NAT instance and disable the managed NAT gateway to lower cost.

Answer

Use VPC peering to a shared services VPC and route all AWS service traffic through that VPC.

Question 7

A startup runs an API on Amazon EC2. The instance must read items from one DynamoDB table and upload logs to one S3 bucket. Platform engineers also need a way to create new application roles, but those roles must never exceed a predefined set of permissions. Which three actions should the architect take? Select three.

Accepted Answer

Attach an IAM role to the EC2 instance profile and remove long-lived access keys from the server.. Option A is correct because attaching an IAM role to the EC2 instance profile allows the instance to obtain temporary credentials via the instance metadata service (IMDS), eliminating the need to store long-lived access keys on the server. This follows the AWS security best practice of using roles for EC2 to securely access DynamoDB and S3 without managing static credentials.

Answer

Give the EC2 instance an IAM user with administrator access for simplicity.

Answer

Store the access keys in the application configuration file and rotate them later.

Question 8

Your company has an internal service hosted behind a Network Load Balancer (NLB) in VPC 10.0.0.0/16. A consumer team in a different VPC (10.1.0.0/16) must call the service without using the public internet. You want private connectivity using AWS PrivateLink. Which configuration best enables least-privilege access while keeping the traffic private?

Accepted Answer

Create a VPC endpoint (interface endpoint) in the consumer VPC that points to the service name published by the provider account, and limit allowed clients using the endpoint’s security group rules.. Option B is correct because AWS PrivateLink uses an interface VPC endpoint in the consumer VPC to connect privately to a Network Load Balancer (NLB) in the provider VPC, keeping traffic within the AWS network. The endpoint’s security group acts as a stateful firewall to restrict which clients in the consumer VPC can access the service, enforcing least-privilege access. This eliminates exposure to the public internet and avoids complex routing or gateway configurations.

Answer

Expose the NLB with an Internet Gateway route and restrict access using a security group attached to the NLB.

Answer

Create an S3 Gateway endpoint in the consumer VPC and store the service hostname in SSM Parameter Store so clients can resolve privately.

Answer

Use a bastion host in the provider VPC and allow the consumer VPC to SSH to it; from there, the consumer makes HTTP calls to the NLB.

Question 9

A CI/CD pipeline needs to deploy to your production environment. Security requires that the pipeline uses temporary credentials (not long-lived access keys) and only has permissions to read a specific set of parameters from AWS Systems Manager Parameter Store and write application logs to CloudWatch Logs. What is the best AWS approach?

Accepted Answer

Create an IAM role in the production account, grant least-privilege policies, and let the CI assume it using STS AssumeRole.. Option B is correct because it uses an IAM role with least-privilege policies that the CI/CD pipeline can assume via AWS STS AssumeRole, generating temporary credentials that automatically expire. This eliminates the need for long-lived access keys and adheres to the security requirement of using temporary credentials. The role's policies can be scoped to exactly read specific parameters from Systems Manager Parameter Store and write logs to CloudWatch Logs.

Answer

Create an IAM user for the pipeline and store access keys in the CI system.

Answer

Attach the required permissions to an IAM group and add the pipeline’s principal to that group directly.

Answer

Use AWS KMS to encrypt the pipeline’s access keys and store the ciphertext in the CI system.

Question 10

A company hosts an internal HTTP API on an internal Network Load Balancer (NLB) in VPC A. A partner team in a separate AWS account needs access, but their VPC CIDR overlaps with VPC A, so VPC peering is not feasible.

Security requirements state the API must remain non-public (no internet-facing ALB/NLB) and access must use AWS private networking.

Which architecture best meets these requirements?

Accepted Answer

Use AWS PrivateLink by creating a VPC endpoint service backed by the NLB in VPC A, then create an interface VPC endpoint in the partner VPC with appropriate endpoint access controls.. Option A is correct because AWS PrivateLink allows you to expose an internal NLB as a VPC endpoint service in VPC A, and the partner team can create an interface VPC endpoint in their own VPC to connect privately. This works even with overlapping CIDR blocks because PrivateLink uses ENIs with private IPs from the endpoint subnet, not routing based on CIDR. The traffic stays within the AWS network and never traverses the internet, meeting the non-public requirement.

Answer

Expose the NLB to the internet with an Elastic IP and restrict access using the NLB’s security group only.

Answer

Use VPC peering between VPC A and the partner VPC and update route tables to resolve the overlap.

Answer

Deploy a NAT gateway in VPC A and route the partner’s traffic to the NLB through the NAT gateway.

Question 11

Company A runs an internal app in account A. The app needs to upload objects to an S3 bucket in account B. When the app calls S3, it receives AccessDenied for s3:PutObject. The team already created an IAM role in account B named UploadRole with a policy allowing s3:PutObject. They did not yet set up any trust relationship. Which change most directly fixes the access problem with least privilege?

Accepted Answer

Update the trust policy on UploadRole (account B) to allow sts:AssumeRole from the app’s IAM role or principal in account A.. The app in account A needs to assume the UploadRole in account B to gain s3:PutObject permissions. Without a trust policy on UploadRole that allows sts:AssumeRole from the app's IAM principal in account A, the role cannot be assumed, and the S3 PutObject call fails with AccessDenied. Updating the trust policy is the most direct fix and follows least privilege by granting only the necessary cross-account role assumption.

Answer

Create IAM user access keys in account A and attach the UploadRole policy directly to those keys.

Answer

Add s3:PutObject permissions to the bucket policy in account B for all principals in account A.

Answer

Attach an SCP (service control policy) in AWS Organizations to deny sts:AssumeRole unless the caller uses an MFA device.

Question 12

An application in account A needs to use an encrypted EBS volume whose snapshots were copied from account B. The EBS volume is encrypted with a customer-managed KMS key in account B. After attaching the volume, the instance fails to mount it and logs show KMS access errors (kms:Decrypt) for the instance role. The instance role in account A already has an IAM policy allowing kms:Decrypt on that key ARN, but the mount still fails. What must be updated in account B to allow the mount to succeed?

Accepted Answer

Update the KMS key policy in account B to allow the instance role’s principal from account A to call kms:Decrypt and kms:CreateGrant.. The instance role in account A has an IAM policy allowing kms:Decrypt on the key ARN, but cross-account KMS access requires the key policy in account B to explicitly grant the external principal (the instance role's ARN) the necessary permissions. Without a key policy statement allowing kms:Decrypt and kms:CreateGrant for the account A role, KMS will deny the decryption request, causing the mount to fail. Option B correctly identifies that the key policy in account B must be updated to authorize the cross-account principal.

Answer

Enable KMS automatic key rotation for the customer-managed key in account B.

Answer

Attach the key policy as an IAM permissions policy to the instance role in account A only; key policies are not evaluated cross-account.

Answer

Disable encryption on the EBS volume until authorization is fixed, then re-enable encryption after mount.

Question 13

An application runs on EC2 instances in private subnets in a VPC. There is no NAT gateway. The instances need to download objects from S3 over HTTPS and also call DynamoDB. The security group outbound rules allow TCP 443 to the VPC endpoint addresses. After deployment, the app times out when connecting to S3, but it can reach DynamoDB. Which single change is most likely to restore S3 connectivity?

Accepted Answer

Create a Gateway VPC endpoint for S3 and associate it with the private subnet route tables that contain the instances.. The application runs in private subnets without a NAT Gateway, so it cannot reach the internet. A Gateway VPC Endpoint for S3 allows private subnet instances to access S3 over the AWS network without internet connectivity. The security group already permits outbound TCP 443 to the endpoint addresses, so the missing piece is the route table association that directs S3 traffic to the endpoint.

Answer

Replace the security group egress rule to allow all outbound traffic to 0.0.0.0/0 on TCP 443.

Answer

Add an Internet Gateway to the VPC and route the private subnet’s 0.0.0.0/0 to the IGW.

Answer

Switch from network ACLs to security groups by removing the existing NACL allow rules for ephemeral ports.

Question 14

Your EC2 instances run in private subnets with no NAT gateway. The instances use the AWS SDK to call STS AssumeRole to obtain temporary credentials for other services. Application logs show errors like: "EndpointConnectionError: Could not connect to https://sts.<region>.amazonaws.com".

Which change most directly resolves this while keeping instances private?

Accepted Answer

Create an interface VPC endpoint for STS (com.amazonaws..sts) and associate it with the instance subnets and a security group that allows HTTPS.. The error indicates the EC2 instances cannot reach the STS public endpoint over the internet because they are in private subnets without a NAT gateway. An interface VPC endpoint for STS (com.amazonaws..sts) allows private, direct connectivity to the STS API using AWS PrivateLink, without requiring internet access. Associating the endpoint with the instance subnets and a security group that allows HTTPS (port 443) resolves the connectivity issue while keeping the instances private.

Answer

Create a gateway VPC endpoint for S3 and route the STS traffic through the S3 endpoint gateway.

Answer

Open an inbound rule in the instances’ security group to allow outbound HTTPS to the internet CIDR block directly.

Answer

Attach an Internet Gateway to the private subnet route table so the STS API can be reached over public internet.

Question 15

A company uses IAM permission boundaries to prevent developers from escalating privileges. The security team created a permission boundary that allows only read-only actions on most AWS services, but teams can still manage their own resources. A developer can create an IAM role with broad permissions, and the boundary does not appear to be restricting it. Which corrective action best aligns with how permission boundaries work?

Accepted Answer

Ensure the role creation process sets the permission boundary on the new role, using the boundary’s ARN in the CreateRole call or role template.. Permission boundaries must be explicitly set on a role during its creation (via the `CreateRole` API call or an infrastructure-as-code template). Without specifying the boundary ARN in the role creation request, the role inherits no boundary, allowing the developer to attach broad permissions that exceed the intended restriction. Option B correctly identifies that the developer’s role creation process must include the boundary ARN to enforce the limitation.

Answer

Rely on an AWS-managed policy attached to the developer’s IAM user; permission boundaries only apply to users.

Answer

Attach the permission boundary policy as an SCP in AWS Organizations so it automatically applies to all roles.

Answer

Grant the developer IAM permissions to add a “deny” statement to the boundary policy so the boundary blocks escalation.