detecting-business-email-compromise

name	detecting-business-email-compromise
description	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,
domain	cybersecurity
subdomain	phishing-defense
tags	["phishing","email-security","social-engineering","dmarc","awareness","bec","fraud"]
version	1.0
author	mahipal
license	Apache-2.0
atlas_techniques	["AML.T0052","AML.T0088"]
nist_ai_rmf	["GOVERN-6.2","MAP-5.2"]
d3fend_techniques	["Restore Object","Restore Configuration","Application Configuration Hardening","Application Hardening","Disable Remote Access"]
nist_csf	["PR.AT-01","DE.CM-09","RS.CO-02","DE.AE-02"]
mitre_attack	["T1566.002","T1534","T1114.002","T1657","T1078.004"]
source	https://github.com/mukul975/Anthropic-Cybersecurity-Skills
source_commit	04450304b12645cb2b974ab96d28c0664758a88d

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)

1. CEO Fraud: Attacker impersonates CEO, requests urgent wire transfer
2. Account Compromise: Employee email compromised, used to request payments from vendors
3. False Invoice Scheme: Fake invoices from "vendor" with changed bank details
4. Attorney Impersonation: Impersonates legal counsel for urgent confidential transfers
5. 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