Investigating Phishing Email Incident

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:
    return {k: re.findall(v, text) for k, v in IOC_PATTERNS.items()}

1. Define Objectives — Clarify the goals and scope for phishing email incident.
2. Gather Resources — Collect tools, data, and access needed for phishing email incident.
3. Execute Process — Carry out phishing email incident operations methodically.
4. Verify Quality — Check results against acceptance criteria.
5. Document Outcomes — Record findings, decisions, and next steps.

Tools

• Analysis Platform — Data processing and visualization
• Collaboration Tools — Team coordination and knowledge sharing

Process

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

Verification

• All phishing email incident 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