<!-- Copyright (c) 2026 defconxt. All rights reserved. -->
<!-- Licensed under AGPL-3.0 — see LICENSE file for details. -->
---
name: performing-email-log-analysis
description: >-
  Collect, parse, and analyze email system logs for security investigations, compliance auditing, and operational troubleshooting.
domain: cybersecurity
subdomain: email-security
tags:
  - email-logs
  - log-analysis
  - mta-logs
  - message-tracking
  - forensics
version: "1.0"
author: defconxt
license: AGPL-3.0
metadata:
  mitre-attack: ["T1114"]
---

# Performing Email Log Analysis

## Overview

Email log analysis is foundational to email security operations. MTA logs,
message tracking data, and authentication records provide the evidence trail
for incident investigation, compliance auditing, and policy enforcement
validation.

## Prerequisites

| Requirement | Install |
|---|---|
| Exchange/Postfix/Sendmail | Access to MTA log files |
| SIEM platform | Log ingestion and query capabilities |
| Python 3.10+ | For agent tooling |
| jq / grep / awk | Command-line log processing tools |

## Key Concepts

### Log Sources

- **MTA logs** — Postfix main.log, Exchange message tracking
- **Authentication logs** — SMTP AUTH, OAuth token grants, IMAP/POP logins
- **Gateway logs** — SEG verdict logs, quarantine actions
- **DNS logs** — SPF/DKIM/DMARC lookup results
- **Audit logs** — Admin actions, mailbox delegation, rule changes

### Key Fields

| Field | Description |
|---|---|
| `MessageId` | Unique message identifier across hops |
| `Sender` | Envelope sender (MAIL FROM) |
| `Recipients` | Envelope recipients (RCPT TO) |
| `ClientIp` | Submitting client IP address |
| `Status` | Delivery status (Delivered, Failed, Quarantined) |

### Analysis Patterns

- **Volume anomalies** — sudden spikes in outbound mail suggest compromise
- **Authentication failures** — brute-force or credential stuffing attempts
- **Relay abuse** — unauthorized relay through misconfigured MTA
- **Delivery failures** — high bounce rates indicate blocklisting
- **Geo anomalies** — logins from unexpected locations

## Workflow

1. **Identify log sources** — catalog available email logs and retention periods
2. **Configure log collection** — forward MTA and auth logs to SIEM
3. **Parse log formats** — build parsers for each log source format
4. **Establish baselines** — compute normal volume, sender, and geographic patterns
5. **Build detection queries** — create alerts for anomalous patterns
6. **Correlate across sources** — join MTA logs with auth and DNS records
7. **Investigate findings** — drill into flagged events with full message context

## Quick Reference

```bash
# Run the agent
node scripts/agent.js analyze --target <scope>
node scripts/agent.js report --target <scope>
```

## Detection

```yaml
title: Email Log Analysis Detection
id: 910383c4-8a2d-4c3a-8461-a3bc0ee43152
status: experimental
description: Detects suspicious activity related to performing email log analysis techniques in email security context
logsource:
  category: email
  service: exchange
detection:
  selection:
    Subject: "*urgent*"
  condition: selection
level: medium
tags:
  - attack.t1114
  - attack.initial_access
falsepositives:
  - Bulk email migration by authorized IT administration tools
```

## Verification

| Check | Method |
|---|---|
| Logs ingested | All email log sources visible in SIEM with < 5 min lag |
| Parsing correct | Key fields extracted accurately from sample messages |
| Baselines set | Volume and pattern baselines computed for 30-day window |
| Alerts firing | Test anomaly triggers alert within detection window |
| Correlation works | MTA + auth log join returns matching records |

## References

- [Postfix Log Format](http://www.postfix.org/postconf.5.html)
- [Exchange Message Tracking](https://learn.microsoft.com/en-us/exchange/mail-flow/transport-logs/message-tracking)
- [RFC 5321 — SMTP Protocol](https://www.rfc-editor.org/rfc/rfc5321)
- [Elastic Common Schema — Email](https://www.elastic.co/guide/en/ecs/current/ecs-email.html)
