Cloud Forensics in GCP: Effective Incident Investigation

Understanding Cloud Forensics: Insights and Challenges

Cloud computing has revolutionized the way digital data is stored, processed, and transmitted. This shift brings immense benefits but also introduces new challenges for digital forensics. Cloud forensics, the application of forensic science to cloud computing environments, is crucial for investigating security incidents, regulatory compliance, and criminal activities in the cloud. This article explores the fundamentals of cloud forensics, the challenges faced, and how emerging NIST standards are addressing these issues.

What is Cloud Forensics?

Cloud forensics involves the application of digital forensic principles in cloud environments to investigate security incidents. It encompasses identifying, acquiring, preserving, examining, interpreting, and reporting potential digital evidence. Cloud forensics differs from traditional forensics due to the cloud’s unique features, such as multi-tenancy, elasticity, and broad network access.

The Importance of Cloud Forensics

As cloud adoption grows, so does the potential for cyber-attacks targeting these environments. Cloud forensics is essential for:

• Investigating organized cybercrimes and policy violations.
• Troubleshooting operational and security issues.
• Monitoring logs to ensure compliance and security.
• Recovering data and systems affected by attacks.
• Assisting in due diligence and regulatory compliance.

Challenges in Cloud Forensics

Conducting forensics in the cloud presents several challenges, as outlined in NIST’s cloud forensic science standards:

• Data Deletion and Overwriting: Recovering deleted or overwritten data in shared virtual environments is complex, as it requires sophisticated mechanisms for access and attribution to specific users.
• Evidence Correlation: Correlating evidence across multiple cloud providers is difficult due to the lack of interoperability and unified log formats.
• Timestamp Synchronization: Accurate time synchronization across multiple geographical regions and endpoints is crucial for reliable forensic analysis.
• Log Capture and Format Unification: Collecting and standardizing log data from various sources in the cloud is challenging but essential for comprehensive forensic investigations.
• Malicious Code and VM Isolation: Ensuring that malicious code does not escape from virtual machines to other parts of the system is vital for maintaining the integrity of forensic evidence.
• Transparency and Trust: The lack of transparency in cloud operations makes auditing and evidence collection difficult. Establishing trust between cloud providers and forensic investigators is crucial.
• Data Location and Chain of Custody: Determining the physical location of data and maintaining a verifiable chain of custody in a distributed, multi-tenant environment is a significant challenge.
• International Legal Issues: Cloud forensics often involves multiple jurisdictions, making legal processes and international cooperation complex and time-consuming.
• Standards and Training: There is a need for standardized processes and training materials to ensure consistency and reliability in cloud forensic investigations.

NIST Standards for Cloud Forensics

The NIST Cloud Computing Forensic Science Working Group (NCC FSWG) aims to address these challenges by developing standards and technologies to improve the accuracy, reliability, and scientific validity of cloud forensics. Key goals include:

• Identifying gaps in technology and standards.
• Developing approaches to mitigate forensic challenges.
• Establishing a Cloud Forensics Reference Architecture.
• Creating standardized tools and techniques for cloud forensic investigations.

Cloud forensics is a vital field that addresses the unique challenges posed by cloud environments. By understanding these challenges and leveraging emerging NIST standards, forensic investigators can improve their ability to conduct thorough and reliable investigations in the cloud. As cloud computing continues to evolve, so must the tools and techniques used to ensure its security and integrity.

How is Cloud Forensics Conducted in Google Cloud Platform (GCP)?

Now that we’ve learned about Cloud Forensics Challenges, let’s explore how cloud computing has become integral to businesses worldwide, offering scalable, flexible, and cost-effective solutions. Transitioning to cloud environments like Google Cloud Platform (GCP) introduces unique challenges for forensic investigations. This article delves into the methodology of conducting cloud forensics in GCP, providing a comprehensive guide on effectively investigating security incidents.

Understanding GCP Forensics

GCP forensics involves acquiring and analyzing evidence from affected containers and virtual machines (VMs) in a forensically sound manner. The primary objectives are to identify the root cause of security incidents, collect necessary evidence, mitigate risks, and ensure business continuity. GCP offers various services, including Google Kubernetes Engine (GKE), which requires a structured approach to incident response and forensic analysis.

Key Objectives of GCP Forensics

• Collecting Artifacts: Gather logs and alerts from various sources to understand the incident’s scope and severity.
• Isolating Affected Containers: Isolate the compromised container to prevent further damage and maintain business operations.
• Snapshot Creation: Create snapshots of the disks of affected VMs for detailed forensic examination.
• Root Cause Analysis: Examine disk snapshots and other evidence to identify the attack’s origin and impact.
• Preventive Measures: Draft a detailed report and implement necessary security controls to prevent future incidents.

Investigating a Security Incident in GCP: Step-by-Step Methodology

Conducting a forensic investigation in GCP involves several critical steps. Here’s a structured approach to guide you through the process:

Step 1: Collect All Logs

Logs are crucial for forensic analysis as they provide detailed records of activities within the GCP environment. Key log sources include:

• Cloud Audit Logs: Capture administrative and data access activities.
• GKE Audit Logs: Record API calls and user actions within GKE clusters.
• Container Logs: Collect logs from running containers, including runtime logs, standard output, and error logs.
• OS Specific Logs: Gather logs from VMs, providing insights into login attempts, network connections, and more.
• VPC Flow Logs: Monitor inbound and outbound traffic, aiding in real-time network analysis.

To ensure log availability during incidents, configure and regularly export logs to destinations like Cloud Storage, Pub/Sub, or BigQuery.

Step 2: Take a Snapshot of the Disk of Host VM

Creating a snapshot of the affected VM’s disk is analogous to imaging a hard drive in traditional forensics. This snapshot can be examined to identify and analyze forensic evidence. You can create snapshots via the Google Cloud Console or gcloud command-line tool.

Using Google Cloud Console:

• Navigate to the Create a Snapshot page.
• Provide a name and optional description for the snapshot.
• Select the disk name of the VM.
• Click Create to generate the snapshot.

Using gcloud:

• Identify the disk name with the command:

gcloud compute instances describe NODE_NAME --zone ZONE_NAME --format="flattened([disks])"

• Create the snapshot:

gcloud compute disks snapshot DISK_NAME --storage-location STORAGE_LOCATION

Step 3: Restrict Access to the Host VM

Limiting access to the compromised VM helps isolate it from the rest of the network, reducing the risk of further compromise.

Node Cordoning and Draining

• Use kubectl to prevent new pods from being scheduled on the node and drain existing pods:

kubectl cordon NODE_NAME

kubectl label pods POD_NAME quarantine=true

kubectl drain NODE_NAME --pod-selector='!quarantine'

Creating a Firewall

• Block all incoming and outgoing traffic to the VM:

gcloud compute firewall-rules create quarantine-egress-deny --network NETWORK_NAME --action deny --direction egress --rules tcp --destination-ranges 0.0.0.0/0 --priority 0 --target-tags quarantine

gcloud compute firewall-rules create quarantine-ingress-deny --network NETWORK_NAME --action deny --direction ingress --rules tcp --destination-ranges 0.0.0.0/0 --priority 1 --target-tags quarantine

Deleting External IP

• Remove the external IP to prevent further external access:

gcloud compute instances delete-access-config NODE_NAME --access-config-name "ACCESS_CONFIG_NAME"

Step 4: Examine the Snapshot Using Docker Explorer

Docker Explorer is an open-source tool that helps forensic investigators examine Docker filesystems offline.

• Mount the Disk Snapshot

mount /dev/sda1 /mnt/root

• List Running Containers

docker-explorer -r /mnt/root/mllib/docker list running_containers

• Examine Specific Containers

docker-explorer -r /mnt/root/mllib/docker mount CONTAINER_ID

Step 5: Redeploy the Container

• If the security vulnerability is identified and fixed, redeploy the container by deleting the compromised pod:

kubectl delete pods POD_NAME --grace-period=10

Step 6: Delete the Workload

• In case of an ongoing attack, delete the workload to stop all associated containers:

kubectl delete deployments DEPLOYMENT

• Manually stop any remaining containers using Docker commands:

docker stop --time TIME_IN_SECONDS CONTAINER

docker kill CONTAINER

docker rm -f CONTAINER

Cloud forensics in GCP is a complex yet essential process for maintaining security and compliance. By following a structured methodology, including collecting logs, creating snapshots, restricting access, and analyzing evidence, forensic investigators can effectively respond to security incidents. Integrating these practices into your incident response plan ensures your organization is well-prepared to handle and mitigate security breaches in the cloud.

Integrate these steps into your GCP forensics strategy with Guilda’s cloud security expertise to boost your incident response capabilities and ensure the integrity of your digital environment.