Conducting Phishing Incident Response

---
name: conducting-phishing-incident-response
description: Use when responding to phishing incidents by analyzing reported emails,
  extracting indicators, assessing credential compromise, quarantining malicious messages
  across the organization, and remediating affected accounts. Covers email header
  analysis, URL/attachment sandboxing, and mailbox-wide purge operations. Activates
  for requests involving phishing response, email incident, credential phishing, spear
  phishing investigation, or phishing remediation.
domain: cybersecurity
tags:
- phishing-response
- email-security
- credential-compromise
- email-header-analysis
- mailbox-remediation
subdomain: incident-response
mitre_attack:
- T1566
- T1204
- T1534
- T1598
version: 1.0.0
author: oyi77
license: Apache-2.0
nist_csf:
- RS.MA-01
- RS.MA-02
- RS.AN-03
- RC.RP-01
category: cybersecurity
---

# Conducting Phishing Incident Response

## Overview

Cybersecurity skill for conducting phishing incident response. Follows industry best practices and security standards.

## When to Use
**Trigger phrases:**
- "conducting phishing incident response"
- "Responds to phishing incidents by analyzing reported emails, extracting indicato"


- A user reports receiving a suspicious email via the phishing report button or abuse mailbox
- Email gateway detects a malicious email that bypassed initial filtering
- Threat intelligence indicates an active phishing campaign targeting the organization
- A user confirms they clicked a link or opened an attachment from a suspicious email
- Credentials have been entered on a suspected phishing page

**Do not use** for business email compromise (BEC) involving compromised internal accounts; use BEC response procedures which focus on account takeover investigation.


## When NOT to Use

- When you lack proper authorization for testing
- For production systems without change management
- When the task requires legal or compliance expertise beyond technical scope


## Prerequisites

- Email security gateway with message trace and quarantine capabilities (Microsoft Defender for Office 365, Proofpoint, Mimecast)
- Microsoft 365 admin access or Google Workspace admin for mailbox search and purge
- Malware sandbox for attachment and URL analysis (ANY.RUN, Joe Sandbox, Hybrid Analysis)
- Email header analysis tools (MXToolbox Header Analyzer, Google Admin Toolbox)
- Identity provider access for account remediation (Azure AD, Okta, Duo)
- Phishing report intake process (dedicated mailbox or integrated report button)

## Workflow

```python
# Example: IOC detection
import re

IOC_PATTERNS = {
    "ip": r"\b(?:\d{1,3}\.){3}\d{1,3}\b",
    "domain": r"\b[a-z0-9-]+\.[a-z]{2,}\b",
    "hash_md5": r"\b[a-f0-9]{32}\b",
    "hash_sha256": r"\b[a-f0-9]{64}\b",
}

def extract_iocs(text: str) -> dict:
    return {k: re.findall(v, text) for k, v in IOC_PATTERNS.items()}
```

1. **Scope the Analysis** — Define what phishing incident response artifacts or data sources to examine and the investigation timeline.
2. **Preserve Evidence** — Create forensic copies of relevant data. Maintain chain of custody documentation.
3. **Extract Key Indicators** — Parse and extract relevant phishing incident response data points from collected artifacts.
4. **Correlate Findings** — Cross-reference extracted data with other sources (threat intel, logs, timelines).
5. **Build Timeline** — Construct a chronological sequence of events related to phishing incident response.
6. **Document Analysis** — Write findings report with evidence, conclusions, and recommendations.

## Tools

- **Forensic Toolkit** — Evidence collection and analysis
- **Timeline Tools** — Chronological event reconstruction
- **Log Analysis Platform** — Centralized log parsing and search


## Process

1. **Reconnaissance** — Gather target information, identify attack surface, enumerate services
1. **Analysis/Exploitation** — Execute the technique, analyze results, document findings
1. **Reporting** — Document IOCs, write findings, provide remediation recommendations

## Verification

- [ ] All phishing incident response procedures executed completely and documented
- [ ] Findings validated against multiple data sources
- [ ] False positives identified and filtered
- [ ] Results documented with evidence and timestamps
- [ ] Recommendations provided with risk-based prioritization

## Anti-Rationalization Table

| Rationalization | Reality |
|---|---|
| "We are too small to be targeted" | Automated attacks target everyone. Size does not matter. |
| "Security slows us down" | A breach slows you down 100x more. Build security in from the start. |
| "We will fix it after launch" | Vulnerabilities in production are exploited within hours. Fix before deploy. |