investigating-phishing-email-incident

name	investigating-phishing-email-incident
description	Investigates phishing email incidents from initial user report through header analysis, URL/attachment detonation, impacted user identification, and containment actions using SOC tools like Splunk, Microsoft Defender, and sandbox analysis platforms. Use when a reported phishing email requires full incident investigation to determine scope and impact.
domain	cybersecurity
tags	["soc","phishing","incident-response","email-security","splunk","defender","sandbox"]
subdomain	soc-operations
mitre_attack	["T1566.001","T1566.002","T1204.001","T1598.003"]
version	1.0
author	oyi77
license	Apache-2.0
nist_csf	["DE.CM-01","DE.AE-02","RS.MA-01","DE.AE-06"]

Investigating Phishing Email Incident

Overview

Cybersecurity skill for investigating phishing email incident. Follows industry best practices and security standards.

When to Use

Trigger phrases:

• "investigating phishing email incident"
• "A user reports a suspicious email via the phishing report button or helpdesk tic"
• "Email security gateway flags a message that bypassed initial filters"
• "Automated detection identifies credential harvesting URLs or malicious attachmen"

Use this skill when:

• A user reports a suspicious email via the phishing report button or helpdesk ticket
• Email security gateway flags a message that bypassed initial filters
• Automated detection identifies credential harvesting URLs or malicious attachments
• A phishing campaign targeting the organization requires scope assessment

Do not use for spam or marketing emails without malicious intent — route those to email administration for filter tuning.

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

• Access to email gateway logs (Proofpoint, Mimecast, or Microsoft Defender for Office 365)
• Splunk or SIEM with email log ingestion (O365 Message Trace, Exchange tracking logs)
• Sandbox access (Any.Run, Joe Sandbox, or Hybrid Analysis) for URL/attachment detonation
• Microsoft Graph API or Exchange Admin Center for email search and purge operations
• URLScan.io and VirusTotal API keys

Workflow

# 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:
     {k: re.findall(v, text)  k, v  IOC_PATTERNS.items()}