SCS-C02 Practice Exam 3 — 20 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

Question 11

During an incident response, a security engineer needs to collect memory and disk forensics from a running EC2 Windows instance without causing the instance to crash. The engineer has AWS Systems Manager SSM Agent installed. Which method should the engineer use?

Accepted Answer

Use AWS Systems Manager Inventory to collect memory and disk information.. Option B is correct because AWS Systems Manager Inventory can collect both memory and disk forensics from a running EC2 Windows instance without causing it to crash. The SSM Agent, already installed, allows Inventory to gather metadata such as running processes (memory) and file system details (disk) via the AWS-CollectInventory document, which is designed for live data collection without rebooting or halting the instance.

Answer

Create an AMI of the instance.

Answer

Use AWS Backup to create a backup of the instance.

Answer

Create an EBS snapshot of the root volume.

Question 12

A company uses AWS Organizations with multiple accounts. The security team wants to ensure that all API calls in the organization are logged and retained for at least one year. Which AWS services or features should be used to meet these requirements? (Choose TWO.)

Accepted Answer

Amazon S3 lifecycle policy to transition logs to S3 Glacier after one year.. Option C is correct because an Amazon S3 lifecycle policy can automatically transition CloudTrail log objects from S3 Standard to S3 Glacier after one year, meeting the retention requirement cost-effectively. Option E is correct because AWS CloudTrail with an organization trail logs all API calls across all accounts in the AWS Organization, ensuring comprehensive logging.

Answer

Amazon GuardDuty with threat detection enabled.

Answer

AWS Config with recording enabled for all resources.

Answer

VPC Flow Logs for all VPCs.

Question 13

A security engineer is investigating a potential data exfiltration incident. The engineer notices large volumes of data being transferred from an Amazon S3 bucket to an external IP address. Which AWS services can be used to detect and alert on such behavior? (Choose THREE.)

Accepted Answer

Amazon CloudWatch Logs with S3 access log analysis.. Amazon CloudWatch Logs can ingest and analyze S3 access logs, which record detailed information about requests made to an S3 bucket, including the source IP address, request type, and bytes transferred. By analyzing these logs with CloudWatch Logs Insights or metric filters, you can detect large data transfers to external IPs and trigger alerts via CloudWatch Alarms, making it a valid detection and alerting mechanism for data exfiltration.

Answer

AWS Config with compliance rules.

Answer

VPC Flow Logs.

Question 14

A security engineer reviews the CloudTrail log entry in the exhibit. The engineer notices that an EC2 instance was launched using an AdminRole. Which additional information would help determine if this is a legitimate action or a potential compromise?

Accepted Answer

The source IP address 203.0.113.50 is from an unexpected geographic location not associated with the company.. The source IP address 203.0.113.50 is from an unexpected geographic location not associated with the company. In CloudTrail, the `sourceIPAddress` field records the originating IP of the API call. If an AdminRole is used from an IP outside the company's known CIDR ranges or geographic regions, it strongly indicates a potential compromise—such as stolen credentials or an attacker using the role from an unauthorized network. This is a key indicator of anomalous behavior in threat detection.

Answer

The AMI ID ami-0abcdef1234567890 is not a standard Amazon-provided AMI.

Answer

The instance type m5.xlarge is unusually large compared to previous launches.

Answer

The security group sg-0123456789abcdef0 allows inbound SSH from 0.0.0.0/0.

Question 15

A security engineer is analyzing the VPC Flow Logs entry in the exhibit. The log shows traffic from an internal IP to an external IP. Which potential security concern should the engineer investigate?

Accepted Answer

An EC2 instance is attempting to connect to an external host on port 3389 (RDP).. The VPC Flow Logs entry shows outbound traffic from an internal IP to an external IP on destination port 3389, which is the default port for Remote Desktop Protocol (RDP). RDP outbound from an EC2 instance to an external host is a security concern because it could indicate an attacker using the instance as a pivot point to connect to an external command-and-control server or to exfiltrate data via an RDP tunnel. The log direction (src internal, dst external) and port 3389 specifically point to an outbound RDP attempt, not inbound scanning or DDoS.

Answer

The instance is participating in a DDoS attack against the external IP.

Answer

An external host is scanning the internal network on port 443.

Answer

The security group allows inbound RDP from 0.0.0.0/0.

Question 16

A security engineer is implementing automated incident response. The engineer wants to use AWS Lambda to automatically remediate GuardDuty findings. What is the recommended pattern to trigger the Lambda function?

Accepted Answer

Configure an Amazon EventBridge rule to match GuardDuty findings and invoke the Lambda function.. Amazon EventBridge is the recommended pattern because it natively integrates with AWS GuardDuty to receive all finding events in near real-time. By configuring an EventBridge rule that matches GuardDuty finding types (e.g., 'UnauthorizedAccess:EC2/SSHBruteForce'), you can directly invoke a Lambda function for automated remediation without polling or intermediate services. This pattern is serverless, event-driven, and follows AWS best practices for decoupled incident response.

Answer

Subscribe the Lambda function to an SNS topic that GuardDuty publishes findings to.

Answer

Use CloudWatch Logs subscription filter to trigger Lambda on GuardDuty log entries.

Answer

Have the Lambda function poll the EC2 instance metadata for threat indicators.

Question 17

A company uses AWS Systems Manager Patch Manager to patch EC2 instances. During a security incident, the security team needs to quickly patch a critical vulnerability across all Windows instances in a specific AWS region. Which steps should the team take? (Choose TWO.)

Accepted Answer

Assign the patch baseline to the instances by specifying a patch group.. Option A is correct because assigning a custom patch baseline to instances via a patch group allows the security team to target specific Windows instances for patching. Patch Manager uses patch groups to associate instances with a specific patch baseline, ensuring only the desired instances receive the critical patch. This approach provides granular control over which instances are patched during an incident.

Answer

Tag all instances with 'PatchGroup=Critical' to include them in the patching.

Answer

Use the AWS-provided default patch baseline for Windows.

Answer

Use SSM Run Command to execute a script that downloads and installs the patch.

Question 18

A company wants to use AWS CloudTrail to monitor data events for all S3 buckets. Which THREE steps are necessary? (Choose THREE.)

Accepted Answer

Specify an S3 bucket to store the log files. Option A is correct because CloudTrail requires a destination S3 bucket to store the log files it generates. Without specifying a bucket, the trail cannot persist logs, and this bucket must have appropriate bucket policies to allow CloudTrail to write logs. This is a mandatory step when creating any trail, whether for management or data events.

Answer

Create a CloudWatch Events rule to forward data events

Answer

Enable CloudTrail Insights to detect unusual data access

Question 19

A security engineer wants to capture all DNS queries made by EC2 instances to detect potential data exfiltration. Which AWS service should be used to log the DNS requests?

Accepted Answer

Use Route 53 Resolver DNS Firewall with query logging. Route 53 Resolver DNS Firewall with query logging is the correct choice because it is specifically designed to log all DNS queries made by EC2 instances that use the Route 53 Resolver. This service captures the domain names being queried, the source IP, and the response, enabling detection of DNS-based data exfiltration (e.g., DNS tunneling). It integrates directly with the VPC's DNS resolver, ensuring all outbound DNS traffic from EC2 instances is logged without additional agents.

Answer

Use Amazon GuardDuty

Answer

Enable VPC Flow Logs

Answer

Enable AWS CloudTrail

Question 20

A company uses AWS CloudTrail to log management events in all regions. The security team notices that some API calls made by an IAM user are not appearing in the CloudTrail event history. What is the most likely reason?

Accepted Answer

CloudTrail event history only retains events for 90 days; older events are not visible. D is correct because CloudTrail event history only retains the last 90 days of events. If the API calls were made more than 90 days ago, they would no longer appear in the event history, even though the trail itself may still be delivering log files to an S3 bucket for longer-term storage. The security team is likely looking at the event history rather than querying the S3 bucket or using Athena for older events.

Answer

The user used the AWS Management Console, not the CLI

Answer

The trail is configured for a single region only

Answer

The API calls were read-only and excluded by default