Pass the Amazon Web Services AWS Certified Specialty SCS-C02 Questions and answers with CertsForce

To ensure that the load balancer only accepts connections over port 443, the security engineer should do the following:

Create a security group with a single inbound rule that allows connections from 0.0.0.0/0 on port 443. This means that the security group allows HTTPS traffic from any source IP address.

Ensure this security group is the only one associated with the ALB. This means that the security group overrides any other rules that might allow HTTP traffic on port 80.

The correct answer is B. Instruct users to run the aws sts get-session-token CLI command and pass the multi-factor authentication --serial-number and --token-code parameters. Use these resulting values to make API/CLI calls.

According to the AWS documentation1, the aws sts get-session-token CLI command returns a set of temporary credentials for an AWS account or IAM user. The credentials consist of an access key ID, a secret access key, and a security token. These credentials are valid for the specified duration only. The session duration for IAM users can be between 15 minutes and 36 hours, with a default of 12 hours.

You can use the --serial-number and --token-code parameters to provide the MFA device serial number and the MFA code from the device. The MFA device must be associated with the user who is making the get-session-token call. If you do not provide these parameters when your IAM user or role has a policy that requires MFA, you will receive an Access Denied error.

The temporary security credentials that are returned by the get-session-token command can then be used to make subsequent API or CLI calls that require MFA authentication. You can use environment variables or a profile in your AWS CLI configuration file to specify the temporary credentials.

Therefore, this solution will resolve the problem of users being unable to perform EC2 commands using the AWS CLI, while still enforcing MFA.

The other options are incorrect because:

A. Changing the value of aws:MultiFactorAuthPresent to true will not work, because this is a condition key that is evaluated by AWS when a request is made. You cannot set this value manually in your policy or request. You must provide valid MFA information to AWS for this condition key to be true.

C. Implementing federated API/CLI access using SAML 2.0 may work, but it requires more operational effort than using the get-session-token command. You would need to configure a SAML identity provider and trust relationship with AWS, and use a custom SAML client to request temporary credentials from AWS STS. This solution may also introduce additional security risks if the identity provider is compromised.

D. Creating a role and enforcing MFA in the role trust policy may work, but it also requires more operational effort than using the get-session-token command. You would need to create a role for each user or group that needs to perform EC2 commands, and specify a trust policy that requires MFA. You would also need to grant the users permission to assume the role, and instruct them to use the sts assume-role command instead of the get-session-token command.

https://docs.aws.amazon.com/cognito/latest/developerguide/user-pool-lambda-post-authentication.html

The AWS documentation states that you can add an outbound allow rule for 192.168.2.0/24 in subnet-2-NACL and add an outbound allow rule for 192.168.1.0/24 in subnet-2-NACL. This will allow the EC2 instances that are running in these two subnets to communicate again.

Understanding Gateway VPC Endpoint:

A gateway VPC endpoint allows traffic from the VPC to specific AWS services (e.g., Amazon S3) without traversing the public internet.

Key Configuration Points to Verify:

The route table is correctly configured to send traffic for Amazon S3 through the gateway VPC endpoint.

IAM permissions and bucket policies are correct and allow access to the specific S3 bucket.

Verify the Endpoint Policy:

Check the VPC endpoint policy to ensure it allows access to the S3 bucket. The policy might be restricting access to certain buckets, prefixes, or IAM principals.

Example VPC Endpoint Policy:

{

"Version": "2012-10-17",

"Statement": [

{

"Effect": "Allow",

"Principal": "*",

"Action": "s3:*",

"Resource": [

"arn:aws:s3:::example-bucket",

"arn:aws:s3:::example-bucket/*"

]

}

]

}

Testing and Validation:

Modify the endpoint policy if required and test access again from the EC2 instance.

Gateway VPC Endpoints Documentation

VPC Endpoint Policies for Amazon S3

AWS Systems Manager Session Manager is a fully managed service that allows you to securely and remotely administer your EC2 instances without the need to open inbound ports, maintain bastion hosts, or manage SSH keys. Session Manager provides an interactive browser-based shell or CLI access to your instances, as well as port forwarding and auditing capabilities. Session Manager works with both Linux and Windows instances, and supports hybrid environments and edge devices.

EC2 Instance Connect is a feature that allows you to use SSH to connect to your Linux instances using short-lived keys that are generated on demand and delivered securely through the AWS metadata service. EC2 Instance Connect does not require any additional software installation or configuration on the instance, but it does require you to use SSH-RSA keys during the launch of new instances.

The correct answer is to use Session Manager, as it provides more security and flexibility than EC2 Instance Connect, and does not require SSH-RSA keys or inbound ports. Session Manager also works with Windows instances, while EC2 Instance Connect does not.

Verified References:

https://docs.aws.amazon.com/systems-manager/latest/userguide/session-manager.html

https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/Connect-using-EC2-Instance-Connect.html

https://repost.aws/questions/QUnV4R9EoeSdW0GT3cKBUR7w/what-is-the-difference-between-ec-2-instance-connect-and-session-manager-ssh-connections

The correct answer is D.

To stop the data exfiltration from the compromised EC2 instances, the security engineer needs to implement a solution that can deny access to any S3 bucket that is outside thecompany’s organization. The solution should also allow the EC2 instances to access the required S3 buckets within the company’s organization for the analysis process.

Option A is incorrect because updating the policy on the S3 gateway endpoint will not affect the access to S3 buckets that are outside the company’s organization. The S3 gateway endpoint only applies to S3 buckets that are in the same AWS Region as the VPC. The compromised EC2 instances can still access S3 buckets in other Regions or other AWS accounts through the internet gateway or NAT device.

Option B is incorrect because updating the policy on the instance profile role will not prevent the compromised EC2 instances from using other credentials or methods to access S3 buckets outside the company’s organization. The instance profile role only applies to requests that are made using the credentials of that role. The compromised EC2 instances can still use other IAM users, roles, or access keys to access S3 buckets outside the company’s organization.

Option C is incorrect because adding a network ACL rule to block outgoing connections on port 443 will also block legitimate connections to S3 buckets within the company’s organization. The network ACL rule will prevent the EC2 instances from accessing any S3 bucket through HTTPS, regardless of whether it is inside or outside the company’s organization.

Option D is correct because applying an SCP on the AWS account will effectively deny access to any S3 bucket that is outside the company’s organization. The SCP will apply to all IAM users, roles, and resources in the AWS account, regardless of how they access S3. The SCP will use the aws:ResourceOrgID and aws:PrincipalOrgID condition keys to check whether the S3 bucket and the principal belong to the same organization as the AWS account. If they do not match, the SCP will deny the S3 actions.