Individual skill
detecting-email-account-compromise
Detect compromised O365 and Google Workspace email accounts by analyzing Unified Audit Logs and Azure AD sign-in logs for impossible travel, inbox rule creation/deletion (Set-InboxRule, New-InboxRule), external mail forwarding rules, and unusual Microsoft Graph API access or OAuth token use. Use when investigating suspected business email compromise (BEC), account takeover, or mailbox persistence via malicious inbox rules.
skills/detecting-email-account-compromise/SKILL.md
Source commit 54a798831d2266a3ca61ce68a7acb80b81160d57
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- Yes
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- Observed behavior
- Local scripts
- Last checked
- Nov 9, 2026
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- Repository stars (not skill ratings)
- 35,926
- Repository last updated
- Aug 31, 2026
- License
- Apache-2.0
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- ai-agents Repository topic
- claude-code Repository topic
- cybersecurity Repository topic
- incident-response Repository topic
- mitre-attack Repository topic
- penetration-testing Repository topic
- red-team Repository topic
- security Repository topic
- cloud-security Repository topic
- malware-analysis Repository topic
- email-compromise Declared skill tag
- office365 Declared skill tag
- microsoft-graph Declared skill tag
- bec Declared skill tag
- inbox-rules Declared skill tag
- sign-in-analysis Declared skill tag
- account-takeover Declared skill tag
- security Derived category
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LICENSEasset · 11,255 bytesSKILL.mdcore · 3,289 bytesreferences/api-reference.mddoc · 2,475 bytesscripts/agent.pyruns · 8,697 bytes
Read excerpt
# Detecting Email Account Compromise
## Overview
Email account compromise (EAC) is a prevalent attack vector where adversaries gain unauthorized access to mailboxes to exfiltrate sensitive data, conduct business email compromise (BEC), or establish persistence through inbox rule manipulation. Attackers commonly create forwarding rules to siphon emails, delete rules to hide evidence, or use OAuth tokens for persistent access. Detection relies on analyzing Microsoft 365 Unified Audit Logs, Azure AD sign-in logs for impossible travel or suspicious locations, inbox rule creation events (Set-InboxRule, New-InboxRule), and Microsoft Graph API access patterns. Key indicators include forwarding rules to external addresses, rules that delete or move messages matching keywords like "invoice" or "payment", and sign-ins from unusual user agents such as python-requests.
## When to Use
- When investigating security incidents that require detecting email account 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