seikaikyo/performing-cloud-forensics-with-aws-cloudtrail

Performing Cloud Forensics with AWS CloudTrail

When to Use

• When investigating suspected AWS account compromise
• After detecting unauthorized API calls or credential exposure
• During incident response involving cloud infrastructure
• When analyzing S3 data exfiltration or IAM privilege escalation
• For post-incident forensic timeline reconstruction

Prerequisites

• AWS account with CloudTrail enabled (management and data events)
• IAM permissions for cloudtrail:LookupEvents, s3:GetObject, athena:StartQueryExecution
• boto3 Python SDK installed
• CloudTrail logs delivered to S3 with optional Athena table configured
• AWS CLI configured with appropriate credentials

Workflow

1. Scope Investigation: Identify timeframe, affected accounts, and compromised credentials.
2. Query CloudTrail: Use boto3 lookup_events or Athena to retrieve relevant API events.
3. Filter by Indicators: Search for suspicious user agents, source IPs, and event names.
4. Reconstruct Timeline: Build chronological sequence of attacker actions from API calls.
5. Analyze Access Patterns: Identify data access, IAM changes, and resource modifications.
6. Identify Persistence: Check for new IAM users, access keys, roles, or Lambda functions.
7. Generate Report: Produce forensic timeline with findings and remediation steps.

Key Concepts

| Concept | Description | |---------|-------------| | LookupEvents | CloudTrail API to query management events (last 90 days) | | Athena Queries | SQL queries against CloudTrail logs in S3 for historical analysis | | User Agent Analysis | Identify tool signatures (AWS CLI, SDK, console, custom) | | AccessKeyId | Track activity by specific IAM access key | | EventName | AWS API action name (e.g., GetObject, CreateUser, AssumeRole) | | sourceIPAddress | Origin IP of API call for geolocation analysis |

Tools & Systems

| Tool | Purpose | |------|---------| | boto3 CloudTrail client | Programmatic CloudTrail event lookup | | AWS Athena | SQL-based analysis of CloudTrail S3 logs | | AWS CLI | Command-line CloudTrail queries | | jq | JSON processing for CloudTrail event parsing | | CloudTrail Lake | Advanced event data store with SQL query support |

Output Format

Forensic Report: AWS-IR-[DATE]-[SEQ]
Account: [AWS Account ID]
Timeframe: [Start] to [End]
Compromised Credentials: [Access Key IDs]
Suspicious Events: [Count]
Source IPs: [List of attacker IPs]
Actions Taken: [API calls by attacker]
Data Accessed: [S3 objects, secrets, etc.]
Persistence Mechanisms: [New users, keys, roles]