Amazon Web Services SCS-C03 AWS Certified Security – Specialty Exam Practice Test

AWS networking best practices require private subnets to access the internet only through NAT gateways located in public subnets. According to the AWS Certified Security – Specialty Study Guide, NAT gateways must be provisioned in public subnets and used as the default route for outbound traffic from private subnets.

Verifying NAT gateways in each Availability Zone ensures high availability and fault tolerance. Updating the private subnet route tables to send 0.0.0.0/0 traffic to the NAT gateway prevents direct internet access while allowing outbound connectivity.

Routing private subnet traffic directly to an internet gateway violates subnet isolation principles. NAT gateways must never be placed in private subnets.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

Amazon VPC Routing and NAT Gateways

AWS Network Segmentation Best Practices

AWS incident response best practices emphasize rapid containment to prevent further data exposure. According to the AWS Certified Security – Specialty Study Guide, the fastest and least disruptive containment method for compromised compute resources is to immediately revoke credentials and permissions rather than modifying data or infrastructure.

Revoking the IAM role’s active sessions prevents the EC2 instance from continuing to access AWS services. Updating the S3 bucket policy to explicitly deny access to the IAM role ensures immediate enforcement, even if temporary credentials remain cached. Removing the IAM role from the instance profile further prevents new credentials from being issued.

Option A and D involve large-scale data movement or re-encryption, which is time-consuming and operationally expensive. Option B relies on network-level controls that do not prevent access through private AWS endpoints.

AWS guidance explicitly recommends credential revocation and policy-based denial as the fastest containment step during active incidents.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

AWS Incident Response Best Practices

AWS IAM Role Session Management

Amazon S3 Block Public Access provides centralized controls to prevent public access through bucket policies and ACLs. AWS Certified Security – Specialty guidance recommends enabling Block Public Access to reduce accidental exposure and to enforce guardrails that override public grants. Enabling Block Public Access on the bucket removes current public exposure when combined with correcting policies/ACLs and prevents future misconfiguration. To ensure the bucket cannot be made public again, the security engineer must prevent principals from disabling Block Public Access. An SCP that denies s3:PutPublicAccessBlock prevents changes that would remove or weaken the PublicAccessBlock configuration, enforcing the guardrail across the OU or account. Options A and D do not directly address public exposure control. Option B denies object reads but does not ensure public access cannot be re-enabled; it also does not address the root misconfiguration pathways and could disrupt legitimate access patterns. Option C specifically combines the correct preventive control (PublicAccessBlock) with organizational enforcement to stop future reversal.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

Amazon S3 Block Public Access

AWS Organizations SCP Guardrails for S3 Controls

Amazon S3 pre-signed URLs grant temporary access based on the permissions of the principal that generates them. AWS Certified Security – Specialty documentation explains that fine-grained authorization can be enforced by combining pre-signed URLs with IAM policy conditions.

By tagging each invoice object with a client identifier and adding a condition to the EC2 instance role policy using s3:ResourceTag/ClientId, the role can generate pre-signed URLs only for objects associated with a specific client. This ensures that each client can access only their own invoices, even though the URLs are temporary and unauthenticated.

Option A over-permissions clients. Option C is unnecessary because instance profiles already use temporary credentials. Option D violates AWS best practices by using long-term credentials.

AWS recommends resource tagging with IAM policy conditions for scalable, secure access control.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

Amazon S3 Pre-Signed URLs

IAM Policy Conditions and Resource Tags

Amazon GuardDuty provides continuous threat detection for compromised instances by analyzing VPC Flow Logs, DNS logs, and CloudTrail events. According to AWS Certified Security – Specialty guidance, GuardDuty is the fastest service to enable for detecting malware and compromised EC2 instances.

To notify the security team, Amazon SNS provides a native email notification mechanism with minimal setup. Amazon EventBridge integrates directly with GuardDuty findings and can filter based on severity. Creating an EventBridge rule that matches high severity GuardDuty findings and publishes to SNS ensures immediate notification.

Security Hub is not required for this use case and adds additional setup time. Amazon SQS does not support email subscriptions.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

Amazon GuardDuty Findings and Severity

Amazon EventBridge Integration with GuardDuty

AWS incident response best practices emphasize isolating compromised resources rather than immediately terminating them. According to AWS Certified Security – Specialty documentation, removing an instance from an Auto Scaling group prevents replacement loops, while applying a restrictive security group isolates the instance for forensic analysis.

Using Amazon EventBridge to trigger an AWS Lambda function enables automated, consistent responses to GuardDuty findings. This approach minimizes disruption to the application because healthy instances continue serving traffic while the affected instance is isolated.

Disabling credentials or modifying network ACLs can have broader impact on unrelated workloads. SNS notifications alone do not provide response automation.

AWS recommends isolate-and-investigate patterns for EC2 incident response.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

Amazon GuardDuty Automated Responses

AWS Incident Response Playbooks

AWS WAF provides managed and custom rules that can immediately mitigate common web exploits such as SQL injection without modifying application code. According to AWS Certified Security – Specialty documentation, placing AWS WAF in front of an Application Load Balancer is a recommended rapid-response control for legacy applications with known vulnerabilities.

Creating an ALB in front of the existing EC2 instances allows seamless traffic migration. AWS WAF SQL injection rules can be deployed and tested without downtime. Updating Route 53 to point to the ALB preserves normal operations. Restricting EC2 security groups afterward prevents bypassing the WAF.

Option B introduces CloudFront changes and single-origin testing, increasing complexity. Option C cannot be completed within 24 hours and risks downtime. Option D is invalid because AWS WAF cannot be attached directly to EC2 instances.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

AWS WAF Web ACL Architecture

AWS Application Load Balancer Security

AWS best practices strongly discourage the use of long-term credentials and recommend cross-account IAM roles with temporary credentials for third-party access. According to the AWS Certified Security – Specialty Study Guide, creating an IAM role in the resource-owning account and allowing a trusted external AWS account to assume that role is the recommended pattern for external access.

By creating the IAM role in the company’s production account and specifying the consultant agency’s AWS account as the trusted principal, the company retains full control over permissions. The trust policy can enforce MFA by using the aws:MultiFactorAuthPresent condition key, ensuring that all access requires MFA. Access is granted through AWS Security Token Service (STS), which issues short-lived credentials.

Option A violates the requirement to avoid long-term credentials. Option B is designed for application user authentication, not AWS account access. Option C incorrectly places the role in the consultant’s account, reducing the company’s control over access.

This solution satisfies MFA enforcement, eliminates long-term credentials, and aligns with AWS third-party access best practices.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

AWS IAM Cross-Account Access

AWS STS and MFA Enforcement

AWS KMS key grants are specifically designed to provide temporary, granular permissions to use customer managed keys without modifying key policies. According to the AWS Certified Security – Specialty Study Guide, grants are the preferred mechanism for delegating key usage permissions to AWS principals for short-term or programmatic access scenarios. Grants allow permissions such as Encrypt, Decrypt, or GenerateDataKey and can be created and revoked dynamically.

Using a key grant avoids the operational risk and overhead of editing key policies, which are long-term control mechanisms and should remain stable. AWS documentation emphasizes that frequent key policy changes increase the risk of misconfiguration and accidental privilege escalation. Grants can be revoked immediately when access is no longer required, ensuring strong adherence to the principle of least privilege.

Options A and D violate AWS security best practices because AWS KMS does not allow direct export of key material unless the key was explicitly created as an importable key, and exporting key material increases exposure risk. Option B requires manual policy changes and rollback, which introduces operational overhead and audit complexity.

AWS recommends key grants as the most efficient and secure way to provide temporary access to KMS keys for applications.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

AWS KMS Key Policies and Grants Documentation

AWS KMS Best Practices

AWS KMS keys are strictly regional resources. According to AWS Certified Security – Specialty documentation, a KMS key created in one Region cannot be used to encrypt or decrypt data in another Region. This includes encrypted RDS and Aurora snapshots.

When copying an encrypted snapshot to a different Region, the destination Region must have its own KMS key. AWS automatically re-encrypts the snapshot using the specified KMS key in the destination Region during the copy operation.

Options C and D are invalid because IAM policies cannot extend a KMS key’s scope across Regions. Option A is incorrect because Secrets Manager does not store or manage KMS keys themselves.

AWS best practices require creating a new customer managed key in the target Region and using it during the snapshot copy process.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

AWS KMS Regional Key Limitations

Amazon RDS Encrypted Snapshot Copy

AWS Config is the AWS service designed to continuously evaluate resource configurations against defined rules. According to the AWS Certified Security – Specialty Study Guide, AWS Config managed rules exist specifically to check database encryption, public accessibility, deletion protection, and log exports for Amazon RDS and Aurora.

AWS Config provides a real-time compliance timeline and displays the compliance state of each resource against each rule at any point in time. This granular visibility is required to assess ongoing compliance with security policies.

Audit Manager generates reports but does not provide continuous compliance monitoring. Security Hub aggregates findings but does not track configuration drift. EventBridge and Lambda introduce unnecessary complexity.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

AWS Config Managed Rules for RDS

AWS Continuous Compliance Monitoring

Amazon Inspector provides native Lambda code vulnerability scanning. GuardDuty focuses on runtime threats, not static code analysis.

Amazon Macie is the AWS service designed to discover and classify sensitive data in S3. Delegated administration enables centralized visibility across an organization. Security Hub aggregates Macie findings for a single-pane-of-glass view.

Inspector does not scan S3 data. Trusted Advisor is not a sensitive data discovery tool.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

Amazon Macie Multi-Account Architecture

Amazon RDS supports point-in-time recovery (PITR) using automated backups within the configured retention window. According to the AWS Certified Security – Specialty Study Guide, PITR allows recovery to any second within the retention period, making it the most precise recovery method following a security incident.

By restoring the database cluster to a point just before the attack occurred, such as 3:14 PM, the security engineer ensures that the restored database reflects the last known good state without including malicious changes. This method is more accurate than restoring from snapshots, which are created at fixed intervals and may not align with the exact recovery time.

Options B and C rely on snapshot timing and may reintroduce compromised data. Option D restores to an arbitrary time and does not meet the requirement to recover to the last known good version.

AWS documentation explicitly recommends point-in-time recovery for incident response scenarios that require precise restoration.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

Amazon RDS Automated Backups and PITR

AWS Incident Response and Recovery Guidance

AWS IAM supports identity federation by allowing external identity providers that use OpenID Connect (OIDC) to authenticate and assume IAM roles. According to the AWS Certified Security – Specialty documentation, IAM OIDC identity providers are the recommended approach for enabling third-party systems, such as external CI/CD pipelines or Git-based repositories, to securely obtain temporary AWS credentials without using long-term access keys.

By creating an OIDC identity provider in IAM and configuring the IAM role trust policy to trust the external IdP, the company enables secure, token-based authentication. The trust policy can include conditions that restrict which repositories, branches, or workflows are allowed to assume the role, enforcing least privilege. AWS Security Specialty guidance emphasizes that this method eliminates static credentials and relies on short-lived tokens issued by the OIDC provider.

Option B is incorrect because IAM Roles Anywhere is designed for workloads running outside AWS that use X.509 certificates, not OIDC. Option C is intended for workforce identity federation, not machine-to-machine authentication. Option D is invalid because AWS RAM does not provide identity federation or authentication capabilities.

This solution aligns with AWS best practices for secure, scalable, and low-overhead authentication for external workloads.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

AWS IAM OIDC Identity Providers

AWS IAM Role Trust Policies

AWS WAF string match rule statements allow inspection of HTTP headers, including the User-Agent header. According to AWS Certified Security – Specialty guidance, when malicious traffic can be uniquely identified by a consistent request attribute, such as a device-specific user agent, a string match rule provides precise mitigation with minimal false positives.

IP-based blocking is ineffective for globally distributed botnets. Geographic blocking risks denying access to legitimate users. Rate-based rules limit request volume but do not prevent low-and-slow attacks.

By matching the unique IoT device brand in the User-Agent header, the security engineer can block only malicious requests while preserving customer access.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

AWS WAF Rule Statements

AWS DDoS Mitigation Best Practices

AWS KMS keys are regional resources and cannot be used across Regions. According to AWS Certified Security – Specialty documentation, applications that are deployed in multiple Regions should use region-specific customer managed keys while referencing keys by alias instead of key ID.

By creating a new customer managed key in eu-north-1 and assigning it the same alias as the key in eu-west-1, the application code can continue to reference the alias without modification. Each Region resolves the alias to the correct local key, ensuring encryption continues to function correctly.

Option A is invalid because KMS keys are regional. Option B requires application changes. Option D introduces unsupported alias patterns.

AWS best practices recommend alias-based key references for multi-Region deployments.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

AWS KMS Regional Keys and Aliases

AWS KMS Best Practices

Amazon S3 Object Lock in compliance mode provides write-once-read-many (WORM) protection, which prevents objects from being modified or deleted for a specified retention period. According to the AWS Certified Security – Specialty Study Guide, compliance mode enforces immutability even for the root user and cannot be overridden.

Enabling S3 Object Lock requires S3 bucket versioning and ensures that once an object is written, it cannot be changed or removed until the retention period expires. This is the strongest protection against data modification and is commonly used for regulatory and legal retention requirements.

Option A can be bypassed by administrators. Option D only protects against deletions, not overwrites. Option C changes encryption but does not prevent modification.

AWS documentation explicitly identifies S3 Object Lock in compliance mode as the correct solution for immutable data storage.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

Amazon S3 Object Lock

Amazon S3 Data Protection and Compliance

Amazon Detective is specifically designed to help security teams investigate and visualize the root cause of security findings. According to AWS Certified Security – Specialty documentation, Detective automatically aggregates and correlates data from GuardDuty, CloudTrail, and VPC Flow Logs to provide interactive visualizations and timelines.

Detective enables investigators to pivot from GuardDuty findings to IAM roles, API calls, network traffic, and resource behavior. This makes it the most efficient tool for understanding how IAM roles were used during suspicious activity.

Amazon Inspector focuses on vulnerability assessment, not behavioral investigation. Security Hub aggregates findings but does not provide deep investigation graphs. Manual analysis with Athena requires significantly more effort.

AWS guidance explicitly recommends Amazon Detective for root cause analysis and visualization of security incidents.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

Amazon Detective Investigation Capabilities

AWS Threat Detection and Analysis

AWS incident response guidance emphasizes immediate containment, credential invalidation, and removal of malicious resources. According to the AWS Certified Security – Specialty documentation, compromised credentials must be rotated or deleted immediately to prevent further unauthorized actions. Rotating or deleting access keys directly mitigates ongoing abuse.

Deleting unrecognized or unauthorized resources, such as the malicious S3 bucket, removes the active threat and limits further damage. Enabling Amazon GuardDuty provides continuous monitoring and helps identify additional compromised resources or malicious behavior that may not yet be visible.

Changing passwords for all IAM users is disruptive and unnecessary if compromise scope is limited. Encrypting CloudTrail logs does not reduce active impact. Taking EBS snapshots is primarily for forensic investigation, not immediate consequence minimization.

AWS best practices recommend GuardDuty activation, credential rotation, and removal of malicious resources as first-response actions.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

AWS Incident Response Best Practices

Amazon GuardDuty Threat Detection

AWS Systems Manager Run Command enables secure, remote execution of commands on EC2 instances without requiring network access or inbound ports. According to the AWS Certified Security – Specialty Study Guide, Run Command is a recommended mechanism for incident response actions such as installing forensic tools, collecting evidence, or applying quarantine controls.

By granting the SSM Agent permission to execute a predefined Run Command document, the security engineer can immediately run the quarantine script across affected instances. This approach supports automation, scalability, and auditability, all of which are critical during security incidents.

Options A, B, and C do not directly enforce quarantine or execute response actions. Tracking versions and storing scripts alone do not trigger incident response.

AWS documentation highlights Systems Manager Run Command as a core capability for automated containment and investigation.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

AWS Systems Manager Run Command

AWS Incident Response Automation

Amazon SQS is a regional service that supports AWS PrivateLink through interface VPC endpoints. According to AWS Certified Security – Specialty documentation, the most secure and compliant way to restrict access to AWS services is by using VPC endpoints combined with resource-based policies.

By creating interface VPC endpoints for Amazon SQS in all VPCs, traffic to SQS remains on the AWS network and does not traverse the public internet. Using the aws:SourceVpce condition in the SQS queue policy ensures that only requests originating from approved VPC endpoints can access the queue. Adding the aws:PrincipalOrgId condition further restricts access to principals that belong to the same AWS Organization.

Security groups and network ACLs do not apply to SQS because SQS is not deployed inside a VPC. Third-party CASB tools add cost and operational overhead.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

Amazon SQS Security and VPC Endpoints

AWS Organizations Condition Keys

Amazon Inspector provides native CI/CD integration capabilities that allow security checks to occur before container images are pushed to Amazon ECR. According to AWS Certified Security – Specialty documentation, Inspector does not block image pushes automatically. Instead, prevention must occur inside the CI/CD pipeline itself.

By generating a Software Bill of Materials (SBOM) using the Amazon Inspector SBOM generator and submitting it to Inspector for scanning, the pipeline can detect critical vulnerabilities before the image is uploaded. If vulnerabilities exceed policy thresholds, the pipeline fails, preventing deployment.

Post-push scanning solutions only detect vulnerabilities after exposure. Event-driven blocking does not prevent the initial risk.

AWS best practices require “shift-left” security controls to prevent vulnerable artifacts from entering production.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

Amazon Inspector CI/CD Integration