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analyzing-cloud-storage-access-patterns

Detect abnormal access in AWS S3, GCS, and Azure Blob Storage by analyzing CloudTrail Data Events, GCS audit logs, and Azure Storage Analytics for after-hours bulk downloads, new-IP access, and API-call spikes (e.g. GetObject) via statistical baselines and time-series anomaly detection. Use when investigating suspected cloud data exfiltration or building related detection rules.

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mukul975/Anthropic-Cybersecurity-Skills
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August 2, 2026 at 16:32
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English
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name
analyzing-cloud-storage-access-patterns
description
Detect abnormal access in AWS S3, GCS, and Azure Blob Storage by analyzing CloudTrail Data Events, GCS audit logs, and Azure Storage Analytics for after-hours bulk downloads, new-IP access, and API-call spikes (e.g. GetObject) via statistical baselines and time-series anomaly detection. Use when investigating suspected cloud data exfiltration or building related detection rules.
domain
cybersecurity
subdomain
cloud-security
tags
["cloud-security","aws-s3","gcs","azure-blob-storage","cloudtrail","data-access-anomaly","exfiltration-detection"]
version
1.0
author
mahipal
license
Apache-2.0
atlas_techniques
["AML.T0024","AML.T0056"]
nist_ai_rmf
["MEASURE-2.7","MAP-5.1","MANAGE-2.4"]
nist_csf
["PR.IR-01","ID.AM-08","GV.SC-06","DE.CM-01"]
mitre_attack
["T1530","T1567.002","T1619","T1078.004","T1048"]
# 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. ```bash python scripts/agent.py --bucket my-sensitive-data --hours-back 24 --output s3_access_report.json ``` ## Examples ### CloudTrail S3 Data Event ```json {"eventName": "GetObject", "requestParameters": {"bucketName": "sensitive-data", "key": "financials/q4.xlsx"}, "sourceIPAddress": "203.0.113.50", "userIdentity": {"arn": "arn:aws:iam::123456789012:user/analyst"}} ```
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