analyzing-cloud-storage-access-patterns

Imported from mukul975/anthropic-cybersecurity-skills (skills/analyzing-cloud-storage-access-patterns/SKILL.md) via skills.sh. Install upstream with npx skills add mukul975/anthropic-cybersecurity-skills --skill analyzing-cloud-storage-access-patterns. Copyright stays with the author (Apache-2.0).

Analyzing Cloud Storage Access Patterns

When to Use

• When investigating security incidents that require analyzing cloud storage access patterns
• When building detection rules or threat hunting queries for this domain
• When SOC analysts need structured procedures for this analysis type
• When validating security monitoring coverage for related attack techniques

Prerequisites

• Familiarity with cloud security concepts and tools
• Access to a test or lab environment for safe execution
• Python 3.8+ with required dependencies installed
• Appropriate authorization for any testing activities

Instructions

1. Install dependencies: pip install boto3 requests
2. Query CloudTrail for S3 Data Events using AWS CLI or boto3.
3. Build access baselines: hourly request volume, per-user object counts, source IP history.
4. Detect anomalies:
   • After-hours access (outside 8am-6pm local time)
   • Bulk downloads: >100 GetObject calls from single principal in 1 hour
   • New source IPs not seen in the prior 30 days
   • ListBucket enumeration spikes (reconnaissance indicator)
5. Generate prioritized findings report.

python scripts/agent.py --bucket my-sensitive-data --hours-back 24 --output s3_access_report.json

Examples

CloudTrail S3 Data Event

{"eventName": "GetObject", "requestParameters": {"bucketName": "sensitive-data", "key": "financials/q4.xlsx"},
 "sourceIPAddress": "203.0.113.50", "userIdentity": {"arn": "arn:aws:iam::123456789012:user/analyst"}}