Tutorial / Cram Notes
Amazon EBS volumes are block-level storage devices that can be used with Amazon EC2 instances. When a security incident is suspected involving instances backed by EBS volumes, it’s important to capture the state of the EBS volume as soon as possible.
- Create EBS Snapshots:
To capture the data on an EBS volume, you can create a snapshot of the volume. Snapshots are point-in-time copies of your volumes that are stored in Amazon S3. To create a snapshot via the AWS Management Console, follow these steps:
- Navigate to the EC2 Dashboard.
- In the “Elastic Block Store” section, click on “Volumes”.
- Select the volume that’s attached to the compromised EC2 instance.
- Right-click on the volume and select “Create Snapshot”.
- Provide a description for the snapshot, for example, “Forensic snapshot – dd/MM/yyyy”.
Alternatively, you can use the AWS Command Line Interface (CLI):
aws ec2 create-snapshot –volume-id vol-xxxxxxxxxxxxx –description “Forensic snapshot – dd/MM/yyyy”
- Lock the Snapshot:
To ensure the forensic integrity of the snapshot, it’s important to lock it to prevent any modifications. AWS provides the ability to create an Amazon Data Lifecycle Manager (DLM) policy to automate the WORM (Write Once Read Many) protection for snapshots.
- Analyze the Snapshot:
Once the snapshot is captured and locked, you can create a new EBS volume from the snapshot and attach it to a separate clean instance for analysis. This allows forensic examination without risking integration with the compromised system.
Memory Dump
Capturing the memory of a compromised instance is another essential step in digital forensics. It can provide insights into the state of the instance’s operating system and running processes at the time of the compromise.
Unfortunately, AWS does not provide a direct feature for capturing memory dumps of EC2 instances; however, you can capture memory data using tools within the instance operating system. It’s important that these tools are installed and available prior to any incident occurring.
Linux Example:
For Linux-based instances, you could use tools like LiME (Linux Memory Extractor) to capture the memory data.
- Install LiME:
First, you need to ensure LiME is installed on your instance before the incident:
sudo apt-get install lime-forensics-dkms
- Capture the Memory:
To capture the memory, you could issue a command similar to:
sudo lime-forensics /dev/sda1 /mnt/forensics/memory_capture.lime
Windows Example:
For Windows-based instances, you could use a tool like WinPmem:
- Install WinPmem:
Much like with Linux, make sure WinPmem is available before an incident.
- Capture the Memory:
Run the tool to capture the memory data:
winpmem.exe C:\forensics\memory_capture.raw
Post Capture Actions
- Secure Data Transfer:
Once the snapshots and memory dumps are captured, it’s critical to transfer them securely to a forensic analysis environment or storage account. Ensure that the transfer uses encryption and the destination is access-controlled.
- Chain of Custody:
Throughout the process, maintain an accurate log for chain of custody, documenting every action taken with the captured data to ensure legal admissibility.
- Analysis:
With the captured data securely stored, a forensic analysis can be conducted. This analysis might involve running various forensic tools to examine file systems, process memory, and logs to reconstruct the activities leading up to and following the compromise.
Conclusion
Properly capturing and handling forensic data from a compromised AWS resource like an EBS volume or EC2 instance memory is an essential part of a comprehensive incident response plan. Utilizing AWS snapshots and third-party memory capture tools, along with following a meticulous documentation process, can help uncover crucial details about a security incident and fortify the security posture of your AWS environment.
Practice Test with Explanation
True or False: Performing a memory dump of a compromised EC2 instance is not recommended as it may alter the state of the evidence.
- Answer: False
Explanation: Capturing a memory dump is a valuable step in forensic analysis as it can provide insights into the running processes and the state of the system at the time of compromise, although it should be done with care to maintain the integrity of the data.
When capturing an Amazon EBS volume snapshot for forensic analysis, should you unmount the volume first?
- A) Yes, always unmount the volume.
- B) No, it’s not necessary to unmount the volume.
- C) It depends on the specific circumstances and the data you’re aiming to preserve.
- D) Amazon EBS snapshots are not useful for forensic analysis.
Answer: C
Explanation: Unmounting the volume can be helpful to ensure data consistency, but it is not always required or feasible. It depends on whether the volume can be taken offline without impacting ongoing investigations or critical systems.
True or False: Amazon EBS snapshots capture data that is in transit over the network.
- Answer: False
Explanation: Amazon EBS snapshots capture the point-in-time state of the storage volume, not the data that is in transit over the network.
Which of the following AWS services can be used to automate the capture of EBS snapshots for forensic purposes?
- A) AWS Lambda
- B) Amazon EC2
- C) AWS Step Functions
- D) All of the above
Answer: D
Explanation: AWS services such as AWS Lambda, Amazon EC2, and AWS Step Functions can all be used to automate the process of capturing EBS snapshots.
True or False: EBS volume snapshots are stored incrementally, and only the blocks on the device that have changed after your most recent snapshot are saved.
- Answer: True
Explanation: Amazon EBS snapshots are indeed incremental, storing only the changes after the last snapshot, which saves on storage costs and improves efficiency.
To ensure the integrity of a forensic snapshot, what is an important step to take?
- A) Run a virus scan on the volume before taking the snapshot.
- B) Write-protect the snapshot after it is taken.
- C) Check the snapshot for encryption before capturing it.
- D) Label the snapshot with a clear description and timestamp.
Answer: D
Explanation: Labeling the snapshot with a clear description and timestamp helps maintain chain of custody and ensures that the evidence can be accurately referenced in the future.
When dealing with a compromised AWS resource, whose responsibility is it to perform the forensic investigation?
- A) AWS
- B) The customer
- C) Third-party forensic experts
- D) It depends on the AWS support plan
Answer: B
Explanation: In the AWS shared responsibility model, the customer is responsible for performing forensic investigations on their instances and data.
True or False: You should perform a forensic investigation as soon as you terminate the compromised instance to ensure data integrity.
- Answer: False
Explanation: You should perform a forensic investigation prior to terminating the instance, as termination will erase in-memory data and dynamic state information that may be crucial to understanding the compromise.
Is it possible to create an EBS snapshot of a volume attached to a running instance without stopping the instance?
- A) Yes, but it may affect the consistency of the data.
- B) No, the instance must be stopped to take an accurate snapshot.
- C) Yes, and it will not affect the data consistency.
- D) No, Amazon EBS does not support snapshotting of volumes attached to running instances.
Answer: A
Explanation: It is possible to create an EBS snapshot of a volume without stopping the instance, though it may impact data consistency, especially for applications writing to disk at the time of the snapshot.
What type of data will NOT be captured by Amazon EBS snapshots?
- A) Data stored on the instance store volumes.
- B) Data on the EBS volume at the time of the snapshot.
- C) Permissions and user access policies for the volume.
- D) Tags associated with the EBS volume.
Answer: A
Explanation: EBS snapshots only capture data on the EBS volume itself at the time of the snapshot and do not include data stored on separate instance store volumes.
Interview Questions
What are the first steps you should take once you have identified a compromised Amazon EBS volume to preserve forensic data?
The first steps include: isolating the instance associated with the compromised EBS volume to prevent further changes, taking a snapshot of the EBS volume to capture the current state for analysis, and ensuring that logging and monitoring with AWS CloudTrail and Amazon CloudWatch are enabled to record all actions.
How do you ensure the integrity of the snapshots for forensic analysis in AWS?
To ensure the integrity, you should enable EBS encryption for the snapshots, restrict access to the snapshots using AWS Identity and Access Management (IAM) policies, and always use the “Copy” function for snapshots to make sure they have not been altered.
Can you explain what a memory dump is, and why it might be important for forensic investigation in the cloud?
A memory dump is an image of what is in an instance’s RAM at a specific point in time. It is important for forensic investigations because it can contain information about the system’s state and activities, including any malware or unauthorized actions that were in memory at the time of the compromise.
How would you capture a memory dump from an EC2 instance that you suspect has been compromised?
To capture a memory dump, I would use tools such as AWS Systems Manager Automation with the “aws:createSnapshot” action, which can help automate the memory dump process from an EC2 instance. Additionally, you could use third-party tools or scripts that leverage the EC2 instance’s operating system capabilities.
When responding to an incident requiring forensic data capture, what AWS services would you utilize to automate and secure the process?
For automation, AWS Systems Manager Automation is a service that can create EBS snapshots. For securing the process, you can use IAM for access controls, AWS Key Management Service (KMS) for encrypting data, and AWS CloudTrail or Amazon CloudWatch for logging and monitoring accesses and actions.
Describe how you would handle chain of custody using AWS services when capturing forensic data?
Chain of custody in AWS can be maintained using a combination of IAM to control and log access, AWS KMS to manage encryption keys, and AWS CloudTrail for logging API calls and actions associated with the forensic data to ensure that all accesses and changes are traceable and auditable.
How do you ensure that your EBS volume snapshots reflect the most recent state of your data?
You ensure this by automating the snapshot creation process at regular intervals using AWS Backup or Amazon Data Lifecycle Manager. It is also advised to immediately create a snapshot when a possible compromise is detected.
What is the significance of Amazon S3 bucket logging in the context of forensic investigation?
Amazon S3 bucket logging provides detailed records for the requests made to a bucket, which can be crucial for a forensic investigation as they help in tracking access patterns, identifying potential unauthorized access, and understanding data exfiltration attempts.
In a situation where a forensic analysis needs to be performed, how important is the segregation of duties within AWS, and how would you achieve it?
Segregation of duties is essential to prevent conflicts of interest and reduce the risk of unauthorized activity. This is achieved by using IAM to create granular permissions and assigning roles based on the least privilege principle.
When dealing with a compromised AWS environment, what is the advantage of using a separate AWS account or VPC for forensics activities?
Using a separate AWS account or VPC provides an isolated environment to conduct forensic activities, minimizing the risk of contaminating evidence and ensuring that forensic operations do not interfere with production workloads.
How do AWS KMS and encryption play a role in protecting forensic data?
AWS KMS allows you to create and control encryption keys used to encrypt your snapshots, ensuring that even if the data is accessed by unauthorized individuals, it remains unreadable without the appropriate permissions to use the keys.
What features of Amazon EBS are beneficial when trying to understand the scope of a security incident during forensic data capture?
Amazon EBS features like snapshot versioning, encryption, and easy integration/logging with AWS CloudTrail facilities understanding the scope of an incident by capturing data states over time while maintaining the security and integrity of the data captured.
Great article! Capturing Amazon EBS volume snapshots is crucial for forensic analysis.
I agree! Snapshots can provide a point-in-time backup of the EBS volumes.
Can someone explain the steps to take a memory dump from an EC2 instance?
Thanks for the helpful information!
Does anyone have experience with forensic data collection in AWS GovCloud?
I found this information very useful for my preparation. Thank you!
While snapshots are useful, what about EBS volume encryption? How does it affect forensic analysis?
Can someone share a script to automate the snapshot process?