ReddRadar
Agent skill
detecting-spearphishing-with-email-gateway
Spearphishing targets specific individuals using personalized, researched content that bypasses generic spam filters. Email security gateways (SEGs) like Microsoft Defender for Office 365, Proofpoint,
Install this agent skill to your Project
npx add-skill https://github.com/autohandai/community-skills/tree/main/detecting-spearphishing-with-email-gateway
SKILL.md
Detecting Spearphishing with Email Gateway
Overview
Spearphishing targets specific individuals using personalized, researched content that bypasses generic spam filters. Email security gateways (SEGs) like Microsoft Defender for Office 365, Proofpoint, Mimecast, and Barracuda provide advanced detection capabilities including behavioral analysis, URL detonation, attachment sandboxing, and impersonation detection. This skill covers configuring these gateways to detect and block targeted phishing attacks.
Prerequisites
- Access to email security gateway admin console
- Understanding of email flow architecture (MX records, transport rules)
- Familiarity with SPF/DKIM/DMARC authentication
- Knowledge of common spearphishing techniques and pretexts
Key Concepts
Spearphishing Characteristics
- Targeted recipients: Specific individuals, often executives or finance staff
- Researched pretexts: References to real projects, colleagues, or events
- Impersonation: Spoofs trusted senders (CEO, vendor, partner)
- Low volume: Few emails to avoid pattern-based detection
- Urgent tone: Creates pressure to act quickly
Gateway Detection Layers
- Reputation filtering: IP/domain/URL reputation scoring
- Authentication checks: SPF, DKIM, DMARC validation
- Content analysis: NLP-based analysis of email body
- Impersonation detection: Display name and domain similarity matching
- URL analysis: Real-time URL detonation and redirect following
- Attachment sandboxing: Behavioral analysis of attachments in isolated environments
- Behavioral analytics: Anomaly detection in communication patterns
Implementation Steps
Step 1: Configure Impersonation Protection
Microsoft Defender for Office 365:
Security > Anti-phishing policies > Impersonation settings
- Enable user impersonation protection for VIPs
- Enable domain impersonation protection
- Add protected users (CEO, CFO, HR Director)
- Set action: Quarantine message
Proofpoint:
Email Protection > Impostor Classifier
- Enable display name spoofing detection
- Configure lookalike domain detection
- Set Impostor threshold sensitivity
Step 2: Configure URL Protection
- Enable Safe Links / URL rewriting
- Enable time-of-click URL detonation
- Block newly registered domains (< 30 days)
- Enable URL redirect chain following
Step 3: Configure Attachment Sandboxing
- Enable Safe Attachments / attachment sandboxing
- Configure dynamic delivery (deliver body, hold attachments)
- Set sandbox detonation timeout to 60+ seconds
- Block macro-enabled Office documents from external senders
Step 4: Create Custom Detection Rules
Use the scripts/process.py to analyze email gateway logs, identify spearphishing patterns, and generate custom detection rules.
Step 5: Configure Alert and Response Actions
- Real-time alerts for impersonation attempts
- Automatic quarantine for high-confidence detections
- User notification with safety tips
- Integration with SIEM for correlation
Tools & Resources
- Microsoft Defender for Office 365: https://security.microsoft.com
- Proofpoint Email Protection: https://www.proofpoint.com/us/products/email-security
- Mimecast Email Security: https://www.mimecast.com/products/email-security/
- Barracuda Email Protection: https://www.barracuda.com/products/email-protection
Validation
- Impersonation protection correctly identifies spoofed VIP display names
- URL detonation catches malicious links in test phishing emails
- Attachment sandboxing detects weaponized documents
- Custom rules trigger on known spearphishing patterns
- SIEM integration receives gateway alerts
Recommended Agent Skills
Expand your agent's capabilities with these related and highly-rated skills.
autohandai/community-skills
mapping-mitre-attack-techniques
Maps observed adversary behaviors, security alerts, and detection rules to MITRE ATT&CK techniques and sub-techniques to quantify detection coverage and guide control prioritization. Use when building an ATT&CK-based coverage heatmap, tagging SIEM alerts with technique IDs, aligning security controls to adversary playbooks, or reporting threat exposure to executives. Activates for requests involving ATT&CK Navigator, Sigma rules, MITRE D3FEND, or coverage gap analysis.
autohandai/community-skills
hunting-for-spearphishing-indicators
Hunt for spearphishing campaign indicators across email logs, endpoint telemetry, and network data to detect targeted email attacks.
autohandai/community-skills
analyzing-malicious-url-with-urlscan
URLScan.io is a free service for scanning and analyzing suspicious URLs. It captures screenshots, DOM content, HTTP transactions, JavaScript behavior, and network connections of web pages in an isolat
autohandai/community-skills
implementing-zero-standing-privilege-with-cyberark
Deploy CyberArk Secure Cloud Access to eliminate standing privileges in hybrid and multi-cloud environments using just-in-time access with time, entitlement, and approval controls.
autohandai/community-skills
implementing-pam-for-database-access
Deploy privileged access management for database systems including Oracle, SQL Server, PostgreSQL, and MySQL. Covers session proxy configuration, credential vaulting, query auditing, dynamic credentia
autohandai/community-skills
detecting-t1003-credential-dumping-with-edr
Detect OS credential dumping techniques targeting LSASS memory, SAM database, NTDS.dit, and cached credentials using EDR telemetry, Sysmon process access monitoring, and Windows security event correlation.
Didn't find tool you were looking for?