Amazon Web Services SCS-C02 - AWS Certified Security - Specialty

The possible steps to troubleshoot this issue are:

A. Ensure that the EC2 instance profile that is attached to the EC2 instances has permissions to create log streams and write logs.This is a necessary step because the CloudWatch agent uses the credentialsfrom the instance profile to communicate with CloudWatch1.

C. Check the CloudWatch agent configuration file on each EC2 instance to make sure that the CloudWatch agent is collecting the proper log files.This is a necessary step because the CloudWatch agent needs to know which logfiles to monitor and send to CloudWatch2.

D. Check the VPC endpoint policies of both VPC endpoints to ensure that the EC2 instances have permissions to use them.This is a necessary step because the VPC endpoint policies control which principals can access the AWS services through the endpoints3.

The other options are incorrect because:

B. Creating a metric filter on the logs is not a troubleshooting step, but a way to extract metric data from the logs. Metric filters do not affect the visibility of the logs in the AWS Management Console.

E. Creating a NAT gateway in the subnet is not a solution, because the EC2 instances do not need internet access to communicate with CloudWatch through the VPC endpoints.A NAT gateway would also incur additional costs.

F. Ensuring that the security groups allow all the EC2 instances to communicate with each other is not a necessary step, because the CloudWatch agent does not require log aggregation before sending. Each EC2 instance can send its own logs independently to CloudWatch.

AWS Backup supports cross-Region backup copy to another backup vault in a different AWS Region. This is the simplest and most operationally efficient method to meet the requirement of geographic redundancy (i.e., data centers several hundred miles apart).

No custom scripting, Lambda, or EventBridge scheduling is required, minimizing operational overhead and aligning with Data Protection and Disaster Recovery best practices.

To mitigate traffic volume from a specific IP address without entirely blocking it, AWS WAF’s rate-based rules are the appropriate solution. AWS WAF (Web Application Firewall) provides rate-based rules that allow a user to count and limit the rate of requests from individual IP addresses.

A rate-based rule tracks the number of requests that each originating IP makes in a rolling five-minute period. If the number of requests exceeds a specified threshold, WAF applies an action such as block or count.

This makes AWS WAF an ideal tool to throttle traffic rather than block it, which directly meets the use case described.

Reference from AWS Certified Security - Specialty Official Guide:

This capability is part of AWS WAF’s standard feature set, explicitly covered under the topics of Logging and Monitoring and Mitigating DDoS and Abnormal Behavior. Rate-based rules are discussed as a method for limiting the number of incoming requests based on request patterns without denying access outright.

The correct answer is B because it checks the configuration of the CloudWatch alarm that is supposed to monitor the CloudTrail log events. The analyst should verify that a metric filter was created to extract the relevant information from the log events, such as the event name, source, and user identity. The analyst should also verify that the metric filter wasmapped to an alarm that triggers when a certain threshold is reached, and that the alarm notification action is set up correctly to send alerts to the analyst1.

The other options are incorrect because they do not address the issue of the CloudWatch alarm not working as expected. Option A is incorrect because CloudTrail and S3 bucket access logging are not related to the monitoring of security group changes. CloudTrail logs the API calls made to AWS services, and S3 bucket access logging records the requestsmade to thebucket2. OptionC is incorrect because CloudWatch dashboards are used to display metrics and alarms in a graphical way, but they do not affect the functionality of the alarm3. Option D is incorrect because the IAM policy permissions for cloudwatch:GetMetricStatistics and cloudwatch:ListMetrics are not required to monitor the CloudTrail log events. These permissions are used to retrieve the statistics and list of metrics for a given namespace4.

For increased security while ensuring functionality, adjusting NACL3 to allow inbound traffic on port 5432 from the CIDR blocks of the application instance subnets, and allowing outbound traffic on ephemeral ports (1024-65536) back to those subnets creates a secure path for database access. Removing default allow-all rules enhances security by implementing the principle of least privilege, ensuring that only necessary traffic is permitted.

When implementing DNSSEC for a subdomain in Amazon Route 53 and encountering a broken trust chain error, creating a Delegation Signer (DS) record in the parent hosted zone is the correct approach. The DS record is essential for establishing the trust chain between the parent and child zones by linking the DNSSEC-signed subdomain to its parentdomain. This step is crucial for DNS resolvers to validate the authenticity of DNS responses, thereby resolving the broken trust chain issue and ensuring the integrity and authenticity of the DNS data for the secured subdomain.

The correct answer is B because it preserves the forensic evidence from the instance in the correct order. The first step is to take a memory snapshot of the instance and store it in an S3 bucket, as memory data is volatile and can be lost when the instance is stopped. The second step is to stop the instance, which will prevent any further changes to the EBS volume. The third step is to take an EBS volume snapshot of the instance and store it in an S3 bucket, which will capture the disk state of the instance. The last two steps are to detach the instance from the Auto Scaling group and deregister it from the ALB, which will isolate the instance from the rest of the application.

The other options are incorrect because they do not preserve the forensic evidence in the correct order. Option A takes the EBS volume snapshot before the memory snapshot, which can result in inconsistent data. Option C detaches and deregisters the instance before taking any snapshots, which can affect the availability of the application. Option D stops the instance before taking the memory snapshot, which can cause the loss of memory data.

Centralize Access Management with IAM Roles:

Create roles in the testing and production accounts with permissions specific to resources in those accounts.

Add a policy that allowssts:AssumeRolefor trusted accounts.

Establish Trust Between Accounts:

Update the trust policies of the roles in the testing and production accounts to allow the roles in the development account to assume them.

Example Trust Policy:

{

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

"Statement": [

{

"Effect": "Allow",

"Principal": {

"AWS": "arn:aws:iam:::role/"

},

"Action": "sts:AssumeRole"

}

]

}

Role Switching for Access:

Developers in the development account can use the AWS Management Console or CLI to assume the roles in the testing or production accounts.

Advantages of This Solution:

Scalability: No need to create individual credentials for each developer in every account.

Security: Credentials are dynamically assumed and not shared across accounts.

Ease of Management: Centralized role management simplifies permissions and reduces administrative overhead.

Cross-Account Access in AWS

Using Roles to Delegate Permissions

IAM Policies and Trust Relationships

To address the issue of an Amazon EC2 instance receiving suspicious requests over an open TCP port, the most effective solution is to update the Network Access Control List (NACL) associated with the subnet where the EC2 instance resides. By adding a deny rule for the specific TCP port and source IP addresses involved in the suspicious activity, the security team can effectively block unwanted traffic at the subnet level. NACLs act as a stateless firewall for controlling traffic in and out of subnets, allowing for broad-based traffic filtering. This measure ensures that only legitimate traffic can reach the EC2 instance, thereby enhancing security without affecting the application's availability to other users. It's a more granular and immediate way to block specific traffic compared to modifying security group rules, which are stateful and apply at the instance level.