<!-- Copyright (c) 2026 defconxt. All rights reserved. -->
<!-- Licensed under AGPL-3.0 — see LICENSE file for details. -->
---
name: implementing-email-quarantine-management
description: >-
  Design and operate email quarantine workflows including policy-based quarantine, admin review, end-user self-service, release procedures, and false positive tracking.
domain: cybersecurity
subdomain: email-security
tags:
  - quarantine
  - email-filtering
  - false-positives
  - policy-tuning
  - email-gateway
version: "1.0"
author: defconxt
license: AGPL-3.0
metadata:
  mitre-attack: ["T1566"]
---

# Implementing Email Quarantine Management

## Overview

Email quarantine isolates suspicious messages for review before delivery or
deletion. Effective quarantine management balances security against usability.
Poor quarantine management leads to either missed threats or business
disruption from blocked legitimate mail.

## Prerequisites

| Requirement | Install |
|---|---|
| Email security gateway | SEG with quarantine capabilities |
| Admin portal access | Quarantine management permissions |
| Python 3.10+ | For agent tooling |
| Notification templates | End-user quarantine digest configuration |

## Key Concepts

### Quarantine Types

- **Spam quarantine** — Messages scored above spam threshold
- **Malware quarantine** — Messages with detected malicious attachments
- **Policy quarantine** — Messages violating DLP or transport rules
- **Phishing quarantine** — Messages flagged by anti-phishing engine
- **Admin quarantine** — Manual quarantine by SOC analyst

### Release Workflow

1. Message quarantined with reason code and verdict confidence
2. Notification sent to admin or end-user (configurable per policy)
3. Reviewer examines headers, content, and attachments in sandbox
4. Decision: release, allow-list, delete, or report false negative
5. Feedback logged for filter tuning

### False Positive Management

Track FP rates by quarantine policy. High FP rates indicate:
- Overly aggressive spam threshold
- Missing allow-list entries for legitimate senders
- DLP policy matching on benign content patterns

## Workflow

1. **Define quarantine policies** — map message categories to quarantine actions
2. **Configure quarantine storage** — set retention period and capacity limits
3. **Set up notification digests** — configure end-user quarantine summaries
4. **Establish review SLA** — define response time for admin quarantine review
5. **Build release procedures** — document safe release verification steps
6. **Implement FP tracking** — log false positive reports with policy context
7. **Tune policies** — adjust thresholds based on FP/FN trend analysis

## Quick Reference

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

## Detection

```yaml
title: Email Quarantine Management Detection
id: 2d174a49-26a2-4265-b636-181303a2c748
status: experimental
description: Detects suspicious activity related to implementing email quarantine management techniques in email security context
logsource:
  category: email
  service: exchange
detection:
  selection:
    Subject: "*urgent*"
  condition: selection
level: medium
tags:
  - attack.t1566
  - attack.initial_access
falsepositives:
  - Bulk email migration by authorized IT administration tools
```

## Verification

| Check | Method |
|---|---|
| Policies active | All quarantine policies show enabled in gateway console |
| Notifications sent | End-user digests delivered on configured schedule |
| Review SLA met | Admin quarantine items reviewed within 4-hour SLA |
| Release works | Released messages delivered to recipient inbox |
| FP tracking | False positive reports logged with policy attribution |

## References

- [Microsoft — Quarantine policies](https://learn.microsoft.com/en-us/defender-office-365/quarantine-policies)
- [Proofpoint — Quarantine Management](https://www.proofpoint.com/us/threat-reference/quarantine)
- [Mimecast — Hold Queue](https://community.mimecast.com/)
- [Google — Email quarantine](https://support.google.com/a/answer/9566803)
