Detect Business Email Compromise (BEC) fraud, where attackers impersonate executives or vendors to trick employees into wire transfers or data disclosure without malicious links, using email gateway rules, behavioral analytics, and financial process controls. Use when investigating a suspected executive/vendor impersonation email or building detection rules for social-engineering fund-transfer fraud.
Triage a suspected business-email-compromise message
Start a fresh conversation. Replace the highlighted placeholders.
Use the detecting-business-email-compromise skill to perform an initial defensive triage of this suspected executive or vendor impersonation email: [paste the email headers and message body]. Use this organizational context: [describe the sender, recipient, normal communication pattern, and payment-change approval process]. Identify relevant BEC indicators, list the evidence that should be verified in email or SIEM logs, and recommend immediate non-destructive validation steps. Do not initiate payments, contact external parties, or modify production controls.
Required inputs
Suspected email headers and message body
Sender and recipient roles
Normal communication patterns
Payment-change and approval process
Relevant email or SIEM log excerpts, if available
Suggested template by Skill Leaderboard, grounded in the linked source. Task evidence ↗
SKILL.md
name: detecting-business-email-compromisedescription: Detect Business Email Compromise (BEC) fraud, where attackers impersonate executives or vendors to trick employees into wire transfers or data disclosure without malicious links, using email gateway rules, behavioral analytics, and financial process controls. Use when investigating a suspected executive/vendor impersonation email or building detection rules for social-engineering fund-transfer fraud.domain: cybersecuritysubdomain: phishing-defensetags: - phishing- email-security- social-engineering- dmarc- awareness- bec- fraudversion: '1.0'author: mahipallicense: Apache-2.0atlas_techniques: - AML.T0052- AML.T0088nist_ai_rmf: - GOVERN-6.2- MAP-5.2d3fend_techniques: - Restore Object- Restore Configuration- Application Configuration Hardening- Application Hardening- Disable Remote Accessnist_csf: - PR.AT-01- DE.CM-09- RS.CO-02- DE.AE-02mitre_attack: - T1566.002- T1534- T1114.002- T1657- T1078.004mitre_f3: version: '1.1' tactics: - initial-access - positioning - monetization - stealth techniques: - id: T1672 name: Email Spoofing tactic: stealth source: attack - id: F1032 name: Impersonate Official tactic: initial-access source: f3 - id: F1036 name: New Vendor Setup tactic: positioning source: f3 - id: F1005.006 name: 'Account Manipulation: Change of Payment Details' tactic: positioning source: f3 - id: F1025.003 name: 'Electronic Funds Transfer: Wire Transfer' tactic: monetization source: f3 - id: F1022 name: Delete Relevant Emails tactic: stealth source: f3
Detecting Business Email Compromise
Overview
Business Email Compromise (BEC) is a sophisticated fraud scheme where attackers impersonate executives, vendors, or trusted partners to trick employees into transferring funds, sharing sensitive data, or changing payment details. Unlike traditional phishing, BEC often contains no malicious links or attachments, relying purely on social engineering. This skill covers detection techniques using email gateway rules, behavioral analytics, and financial process controls.
When to Use
When investigating security incidents that require detecting business email compromise
When building detection rules or threat hunting queries for this domain
When SOC analysts need structured procedures for this analysis type
When validating security monitoring coverage for related attack techniques
Prerequisites
Email security gateway with BEC detection capabilities
Understanding of organizational financial processes and approval chains
Access to email logs and SIEM platform
Knowledge of social engineering tactics
Key Concepts
BEC Attack Types (FBI IC3 Classification)
CEO Fraud: Attacker impersonates CEO, requests urgent wire transfer
Account Compromise: Employee email compromised, used to request payments from vendors
False Invoice Scheme: Fake invoices from "vendor" with changed bank details
Attorney Impersonation: Impersonates legal counsel for urgent confidential transfers
Data Theft: Requests W-2, tax forms, or PII from HR
Detection Indicators
Urgency and secrecy language ("confidential", "do not discuss with others")
New or changed payment instructions
Executive communication outside normal patterns
Display name matches executive but email domain differs
Reply-to address differs from From address
First-time communication pattern between sender and recipient
Request for gift cards or cryptocurrency
Workflow
Step 1: Configure BEC-Specific Email Rules
Flag emails with VIP display names from external domains
Detect financial keywords combined with urgency language
Alert on first-time sender to finance/accounting staff
Check for Reply-To domain mismatch
Step 2: Deploy Behavioral Analytics
Baseline normal communication patterns per user
Detect anomalous requests (unusual recipient, unusual time, unusual request type)
Monitor for email forwarding rule changes (T1114.003)
Step 3: Implement Financial Controls
Dual-authorization for wire transfers above threshold
Out-of-band verification for payment detail changes (phone callback)
Vendor payment change verification process
Finance team training on BEC red flags
Step 4: Monitor for Account Compromise
Detect impossible travel in email login locations
Alert on email forwarding rule creation
Monitor for mailbox delegation changes
Check for inbox rules hiding BEC-related emails
Tools & Resources
Microsoft Defender for O365 Anti-BEC: Built-in BEC detection