SCS-C02 Practice Test 5 — 10 Questions

Question 1

A company has multiple AWS accounts managed through AWS Organizations. The security team needs to ensure that no EC2 instances are launched without an approved Amazon Machine Image (AMI). Which governance control should be implemented?

Accepted Answer

Use a service control policy (SCP) that denies ec2:RunInstances unless the AMI ID is in an approved list.. A service control policy (SCP) is the correct governance control because it operates at the AWS Organizations level, allowing the security team to enforce a deny on ec2:RunInstances across all member accounts unless the AMI ID matches an approved list. SCPs are account permission boundaries that cannot be overridden by IAM policies within the account, ensuring that no user or role can launch an EC2 instance with an unapproved AMI, even if they have full administrative privileges. This provides a preventive control that blocks non-compliant actions before they occur, which is more robust than detective or reactive measures.

Answer

Deploy an AWS Config rule that triggers a Lambda function to terminate non-compliant instances.

Answer

Use AWS CloudTrail to monitor instance launches and alert the security team.

Answer

Use an IAM policy that restricts ec2:RunInstances to approved AMIs.

Question 2

Refer to the exhibit. A security engineer applied the bucket policy shown. What is the effect of this policy?

Accepted Answer

Only GetObject requests that use HTTP are denied.. The bucket policy uses a `NotIpAddress` condition with the `aws:SourceIp` key to deny `s3:GetObject` requests that do not originate from the specified IP range (192.0.2.0/24). However, the `Null` condition on `aws:SecureTransport` ensures the policy only applies when the request is not using HTTPS (i.e., when `aws:SecureTransport` is false). Therefore, only GetObject requests over HTTP are denied; HTTPS requests from any IP are allowed, and PutObject requests are unaffected.

Answer

All PutObject requests are denied.

Answer

Only GetObject requests from specific IP ranges are denied.

Answer

All GetObject requests to the bucket are denied.

Question 3

Which TWO steps should a security engineer take when responding to a confirmed security incident involving a compromised EC2 instance? (Choose 2.)

Accepted Answer

Isolate the instance by changing its security group to deny all traffic. Preserving the instance (snapshot) and isolating it (security group change) are key steps. Terminating immediately destroys evidence. Deleting logs is wrong. Reimaging without investigation destroys evidence.

Answer

Reimage the instance from a clean AMI immediately

Answer

Delete all CloudTrail logs related to the instance

Answer

Immediately terminate the instance to stop the attack

Question 4

A security engineer needs to ensure that all EC2 instances launched in a development account are tagged with a cost center. What is the most effective way to enforce this?

Accepted Answer

Use an IAM policy that denies ec2:RunInstances unless the request includes the cost center tag. Option D is correct because using an IAM policy with a condition key (e.g., `aws:RequestTag`) that denies `ec2:RunInstances` unless the `cost center` tag is specified in the API call enforces tagging at launch time. This prevents any untagged instance from being created, providing proactive enforcement rather than reactive detection or remediation.

Answer

Use AWS Config to detect untagged instances and send alerts

Answer

Use AWS Systems Manager to tag instances after launch

Answer

Create a tag policy in AWS Organizations requiring the cost center tag

Question 5

A company runs a multi-account AWS environment using AWS Organizations. The security team uses AWS Config to monitor compliance. Recently, they noticed that a developer in the 'development' account created an S3 bucket that is publicly accessible. The security team wants to prevent this in the future by automatically remediating any public S3 bucket. They have an SCP that denies s3:PutBucketPublicAccessBlock, but developers are still making buckets public by using bucket ACLs. The security team wants to implement a solution that automatically fixes any bucket that becomes public. Which solution should they choose?

Accepted Answer

Use AWS Config with the s3-bucket-public-read-prohibited managed rule and an automatic remediation action using AWS Systems Manager Automation. Option B is correct because AWS Config's s3-bucket-public-read-prohibited managed rule evaluates S3 bucket ACLs and policies for public read access. When a noncompliant bucket is detected, an automatic remediation action using AWS Systems Manager Automation can invoke a custom SSM document (e.g., AWS-DisableS3BucketPublicReadWrite) to remove public ACLs or apply a bucket policy that denies public access. This provides automated, event-driven remediation without relying on manual intervention or incomplete SCPs.

Answer

Use CloudTrail to detect PutBucketAcl events and send to SNS for manual remediation

Answer

Update the SCP to deny s3:PutBucketAcl with a condition for public access

Answer

Attach an IAM policy to all users that denies s3:PutBucketAcl

Question 6

Refer to the exhibit. A security engineer finds the above IAM policy attached to an IAM group. The policy is intended to allow all EC2 actions only from the corporate network (10.0.0.0/8). However, users report that they can perform EC2 actions from outside the corporate network. What is the MOST likely reason?

Accepted Answer

The aws:SourceIp condition key does not apply to API calls made through the AWS Management Console; the console uses AWS IP addresses.. Option C is correct because the `aws:SourceIp` condition key does not evaluate the source IP of requests made through the AWS Management Console. When a user signs in to the console, the console makes API calls on their behalf using AWS service endpoints, which have AWS-owned IP addresses, not the user's corporate IP. Therefore, the condition `IpAddress` fails, and the policy denies console-based EC2 actions from the corporate network, but the policy actually allows all EC2 actions (since the default effect is Allow) when the condition is not met? Wait—the policy has an Allow effect with a condition; if the condition is not met, the Allow does not apply, but there is no explicit Deny, so other policies or the default implicit Deny would block the action. However, the question states users can perform EC2 actions from outside the corporate network, meaning the policy is not blocking them. The most likely reason is that the console uses AWS IP addresses, so the condition never matches, and the Allow never applies, but users are still able to perform actions because they are using the console? Actually, the console uses AWS IPs, so the condition `IpAddress` would not match, and the Allow would not apply, leading to implicit Deny—but users report they can perform actions. This indicates that the policy is not the only one; perhaps there is another policy allowing EC2 actions without conditions (Option A). But the question asks for the MOST likely reason given the exhibit and the intent. The trap is that the `aws:SourceIp` condition does not work for console-based API calls because the console uses AWS IP addresses, so the condition is effectively ignored for console users, allowing them to bypass the intended restriction. This is a well-known limitation documented by AWS.

Answer

The IAM group has an additional policy that allows all EC2 actions without conditions.

Answer

The policy allows access to all EC2 actions, but the condition only applies to the ec2:* actions, which includes all EC2 actions.

Answer

The policy should use a NotIpAddress condition instead of IpAddress.

Question 7

A security engineer is designing a solution to allow an external auditor to access logs in an S3 bucket in the company's AWS account. The auditor does not have an AWS account. The engineer needs to grant read-only access to the specific bucket for a limited time. Which TWO actions should the engineer take? (Choose two.)

Accepted Answer

Use AWS STS to issue temporary credentials that the auditor can use to access the bucket.. Option C is correct because AWS Security Token Service (STS) can issue temporary, limited-privilege credentials (access key, secret key, and session token) that the auditor can use to authenticate API requests to the S3 bucket. This approach does not require the auditor to have an AWS account and allows the engineer to control the validity period (via the DurationSeconds parameter) to enforce a limited time window. Option D is correct because a pre-signed URL embeds temporary credentials and a specific expiration time, granting read-only access to a single object without requiring the auditor to have AWS credentials or an AWS account.

Answer

Enable S3 Access Analyzer on the bucket to generate findings for the auditor.

Answer

Create a cross-account IAM role in the company's account and share the role ARN with the auditor.

Answer

Configure the bucket policy to grant access to 'Principal': '*' with a condition that limits access to the auditor's IP address.

Question 8

Refer to the exhibit. An AWS KMS key policy includes the statement shown. The AdminRole tries to decrypt a ciphertext that was encrypted using the same KMS key with encryption context 'department=engineering'. What will happen?

Accepted Answer

The decrypt operation fails because the encryption context does not match the condition.. Option D is correct because the KMS key policy includes a condition that requires the encryption context to match 'department=engineering'. When the AdminRole attempts to decrypt the ciphertext, the encryption context used during decryption must exactly match the context used during encryption. Since the policy enforces this condition with a kms:EncryptionContextKeys condition key, the decrypt operation fails if the context does not match, even though the role has kms:Decrypt permission.

Answer

The decrypt operation succeeds because the role has kms:Decrypt permission.

Answer

The decrypt operation succeeds because the encryption context is ignored during decryption.

Answer

The decrypt operation fails because the policy does not allow kms:Decrypt without matching context.

Question 9

During a security incident, a security engineer needs to verify whether an EC2 instance's security group allowed inbound SSH from a specific IP address at the time of the incident. Which AWS service or feature should the engineer use to obtain this historical information?

Accepted Answer

AWS Config configuration history.. AWS Config configuration history records changes to security group rules, including the addition or removal of inbound SSH allow rules. By querying the configuration history for the specific security group, the engineer can determine the exact state of the rules at the time of the incident, including whether a specific IP address was allowed. This is the only service that provides a historical record of security group rule configurations.

Answer

Amazon CloudTrail event history.

Answer

AWS Systems Manager Inventory.

Answer

VPC Flow Logs.

Question 10

A security engineer is configuring an AWS environment to detect and respond to potential security threats. Which AWS service can be used to automate the remediation of unwanted access to Amazon S3 buckets by invoking AWS Lambda functions?

Accepted Answer

Amazon GuardDuty. Amazon GuardDuty is a threat detection service that continuously monitors for malicious activity and unauthorized behavior across AWS accounts and workloads. It can integrate with AWS Lambda functions via CloudWatch Events to automate remediation actions, such as blocking unwanted access to S3 buckets by updating bucket policies or removing public access. This makes GuardDuty the correct choice for detecting and automatically responding to security threats against S3 resources.

Answer

AWS Config

Answer

Amazon Inspector

Answer

AWS WAF