Cloud forensics is a branch of digital forensics that focuses on investigating and analyzing incidents in cloud environments. It involves collecting, preserving, and examining digital evidence from cloud services to understand security breaches, data theft, or malicious activities.
Since cloud data is stored across remote servers, and infrastructure is managed by third parties, cloud forensics comes with unique challenges like limited access to physical hardware and reliance on provider logs.
Key Artifacts in Cloud Forensics
- Access Logs: User logins, IP addresses, device info, and failed login attempts — useful for tracking access patterns and detecting brute-force attacks.
- API Call Histories: Records of API requests, including timestamps, accounts, parameters, and response codes — critical for spotting unauthorized actions or data exfiltration.
- Network Traffic Logs: VPC flow logs, firewall logs, and DNS queries — helpful for detecting suspicious traffic, potential breaches, and anomalous connections.
- Virtual Machine Snapshots: Full disk images, memory dumps, running processes, and open connections — useful for post-incident analysis and threat hunting.
- Storage Bucket Access Records: Logs of file access, modifications, downloads, and access control changes — key for investigating data theft or tampering.
- IAM Logs: User creation, role changes, policy edits, and temporary credentials — essential for tracking privilege escalation and insider threats.
- Configuration Change Histories: Logs of infrastructure changes, security settings, and network updates — useful for identifying misconfigurations and security gaps.
- Billing and Usage Data: Resource consumption metrics, cost spikes, and data transfer patterns — can reveal cryptojacking or resource abuse.
- Database Logs: Query logs, schema changes, privilege updates, and backup records — critical for detecting unauthorized data access or tampering.
- Serverless Function Logs: Function executions, error reports, and input/output data — helpful for understanding what code ran and spotting function abuse.
- Container Orchestration Logs: Container lifecycle events, image deployments, scaling logs, and inter-service communications — useful for tracking malicious activity within microservices.
Investigation Methods in Cloud Forensics
1. Identify Relevant Cloud Services & Data Sources:
Start by understanding the cloud setup and figuring out which services were running during the incident. Collect evidence from different cloud layers (like infrastructure, platforms, and software). Check what logs and audit tools the provider offers.
2. Preserve Volatile Data:
Capture live system memory and take snapshots of running virtual machines to save their current state. Collect live network traffic and record active user sessions and system configurations.
3. Collect Artifacts with Provider Tools:
Use the cloud provider’s tools (like AWS CloudTrail or Azure Monitor) to collect logs and other data. APIs and automated scripts can help gather large amounts of data quickly. Make sure everything is collected in a way that preserves its integrity.
4. Establish Chain of Custody:
Keep detailed records of how you collected the data, who accessed it, and when. Use encryption and make multiple copies of the evidence to prevent tampering or loss.
5. Perform Timeline Analysis:
Align timestamps from different sources and create a timeline of events. Look for patterns, anomalies, and key activities that happened around the incident. Visualization tools can help make sense of complex sequences.
6. Correlate Data Across Multiple Sources:
Combine logs and events from various services to get the full picture. Link user actions across platforms, and use machine learning to spot hidden patterns or connections.
7. Use Specialized Forensic Tools:
Leverage cloud-specific tools like Cellebrite Cloud Analyzer or Magnet AXIOM for analysis. Use log analyzers and network forensic tools to dig deeper into collected data.
8. Reconstruct the Incident:
Piece together the sequence of events to understand how the incident happened, the attacker’s actions, and the full impact. Identify vulnerabilities and check if any threats still exist.
9. Conduct Data Recovery:
Try to recover deleted files, analyze metadata, and examine backups or transaction logs. Advanced techniques can help reconstruct fragmented or partially deleted data.
10. Perform Malware Analysis (if needed):
If malware is suspected, isolate and analyze it in a safe environment. Reverse-engineer the code to figure out what it does, and see if it tried to steal data or maintain access.
11. Validate Findings and Peer Review:
Double-check findings with another investigator, test alternative explanations, and ensure every conclusion is backed by solid evidence. Prepare for the possibility of defending your findings in court.