Microsoft Purview Audit
Unified Audit Log search, insider-threat investigation and evidence export across Microsoft 365.
Difficulty
Intermediate
Environment
Microsoft 365 / Purview
Deployment
Production
Est. Implementation
1–2 weeks
Executive Summary
This project documents an enterprise Microsoft Purview Audit implementation — verifying audit is enabled, running a targeted audit search, investigating a focused insider-threat scenario, and exporting evidence for compliance and forensic use.
Using Audit (Standard), a search scoped to a single user, activity type and three-day window returned 12 FileAccessed events, which were reviewed, exported to CSV with full AuditData JSON, and validated in Excel — demonstrating a repeatable, evidence-producing investigation workflow.
Business Problem
There was no visibility into who accessed sensitive SharePoint documents, no accountability record for file deletions, no systematic review of privileged account actions, and security incidents were investigated reactively without data.
Regulatory auditors require evidence of monitoring controls; without a searchable, exportable audit trail the organisation cannot demonstrate accountability or respond quickly to a suspected incident.
Business Risks
- No visibility into who accessed sensitive SharePoint documents
- File deletions occur with no accountability record
- Privileged account actions not reviewed systematically
- Security incidents investigated reactively, without data
Compliance Concerns
- ISO/IEC 27001:2022 monitoring and logging controls
- GDPR Article 5 accountability requirements
- Evidence retention for regulatory audits
Solution Overview
Microsoft Purview Audit (Standard) centralises activity from Exchange Online, SharePoint Online, OneDrive, Teams and Entra ID into the Unified Audit Log, searchable by date range, user, activity type and workload.
A targeted investigation scenario — a single test user's FileAccessed activity over a three-day window — was executed end to end: search, results review, CSV export with full AuditData JSON, and validation of the export in Excel, producing chain-of-custody evidence ready for compliance or legal use.
Architecture
Architecture diagram placeholder
Technology Stack
Microsoft Purview Audit
Unified Audit Log search, filters and export
Audit Standard
90-day retention, full search, CSV export (E3/E5)
Exchange Online / SharePoint / OneDrive / Teams
Audited Microsoft 365 workloads
Microsoft Entra ID
Administrator authentication and audit role assignment
PowerShell
Targeted search, bulk export and configuration auditing
Lab Environment
- Tenant
- securem365lsb.onmicrosoft.com (Microsoft 365 E5 trial)
- Audit Tier
- Audit Standard
- Test Account
- testuser1@securem365lsb.onmicrosoft.com
- Investigation Window
- 2026-07-01 to 2026-07-03
- Investigation Scenario
- Insider Threat — file access pattern analysis
- Events Captured
- 12 FileAccessed events
Implementation
A phased, expandable walkthrough. Screenshots and evidence can be attached to each phase.
Confirm auditing is enabled and administrator roles are assigned.
- Navigate to compliance.microsoft.com → Solutions → Audit
- Confirm auditing status is enabled for the tenant
- Verify Audit Logs / View-Only Audit Logs roles are assigned
Screenshots for this phase can be added here.
PowerShell
Illustrative example snippets — copy or download each script. Production values are placeholders.
Targeted Unified Audit Log search
# Illustrative scaffold based on Search-UnifiedAuditLog.ps1
.\Search-UnifiedAuditLog.ps1 `
-StartDate "2026-07-01" `
-EndDate "2026-07-03" `
-UserIds "testuser1@securem365lsb.onmicrosoft.com" `
-Operations "FileAccessed" `
-OutputPath "C:\AuditExports"Bulk audit export
# Illustrative scaffold based on Export-AuditLogs.ps1
Search-UnifiedAuditLog -StartDate (Get-Date).AddDays(-3) -EndDate (Get-Date) `
-RecordType SharePointFileOperation |
Export-Csv -Path .\AuditExports\audit-export.csv -NoTypeInformationConfiguration Screenshots
Click any tile to open the lightbox. Real screenshots will replace these placeholders.
Phase 2–3 · Audit Search
Phase 4 · Export Results
Phase 5 · Validation
Validation
Audit Solution Accessible
Audit accessible at compliance.microsoft.com → Solutions → Audit.
Search Executes with Filters
Date, user and activity filters apply correctly.
12 Results Returned
Search completes with 12 results for testuser1 FileAccessed.
Results Display Correctly
Activity, User, IP, Date and RecordType fields all visible.
Export Succeeds
Export completes and CSV downloads successfully.
CSV Validated in Excel
All 12 records and AuditData JSON confirmed intact.
Challenges
Audit is enabled by default — but must be verified
Many organisations assume auditing is active without checking; this was verified explicitly before relying on it for an investigation.
Search scope affects performance
Broad date ranges across all users can be slow; scoping to a specific user, activity and date range returned results faster and was easier to analyse.
Lessons Learned
- AuditData JSON is the forensic record — CSV columns are metadata, but AuditData contains the complete activity context.
- Export early — Audit Standard retains logs for only 90 days; preserve evidence immediately once an incident is identified.
- Audit Premium is required for mailbox-read events (MailItemsAccessed), which are critical for email breach investigations.
- Targeted searches (specific user, activity, date range) are faster and easier to analyse than broad searches.
Business Impact
12 events in one search
Investigation Time
Chain-of-custody CSV
Evidence Preserved
Searchable audit trail
Improved Accountability
ISO 27001 evidence
Audit-Ready
Skills Demonstrated
Related Certifications
Certifications this project maps to are highlighted.
Related Blog Articles
Placeholder cards — future TechCertGuide integration.
GitHub Repository
lokeshm-it/Microsoft-Purview-Audit
PublicUnified Audit Log search, investigation workflow and evidence export implementation.
Download Center
Project Case Study
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Architecture Diagram
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PowerShell Scripts
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Technical Documentation
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