Azure Entra: Guest User Invitation Failed When Initiated by Non-Privileged User

Identifies failed guest user invitations in Azure audit logs when the inviter lacks required permissions.

FreeReviewedSigma · Medium · v5

Product: azure
Service: auditlogs
Author: Mark Morowczynski '@markmorow', Yochana Henderson, '@Yochana-H' (SigmaHQ), DRL 1.1
Published: 2022-08-10
Updated: 2026-07-31

ATT&CK techniques

Initial Access → Defense Evasion

Recon
Resource Dev
Initial Access
- T1078.004Cloud Accounts
Execution
Persistence
- T1078.004Cloud Accounts
Priv Esc
- T1078.004Cloud Accounts
Defense Evasion
- T1078.004Cloud Accounts
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule catches failed attempts to invite an external/guest user where the action is issued by an account that lacks permission to invite guests. Attackers may probe or attempt privilege escalation by repeatedly triggering guest invitation operations until a success condition is met. The detection relies on Azure audit log events that include the invitation message and a failure status.

Reporting behind it

Related detections9 linkedT1078.004 — drag to rearrange

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Azure Entra: Guest User Invitation Failed When Initiated by Non-Privileged User

Pivot detection · T1078.004 · 9 related

Changelog

v5
Candidate ingested via manual entry.2026-07-31
v4
Candidate ingested via manual entry.2026-07-31
v3
Candidate ingested via manual entry.2026-07-31
v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

azure-ad-audit-logs-failed-guest-invitation-by-non-authorized-inviter-0b4b72e3

title: "Azure Entra: Guest User Invitation Failed When Initiated by Non-Privileged User"
id: 197d889d-d287-430d-bfa1-50c56d5b2d61
status: test
description: This rule catches failed attempts to invite an external/guest user where the action is issued by an account that lacks permission to invite guests. Attackers may probe or attempt privilege escalation by repeatedly triggering guest invitation operations until a success condition is met. The detection relies on Azure audit log events that include the invitation message and a failure status.
references:
  - https://learn.microsoft.com/en-us/entra/architecture/security-operations-privileged-accounts#things-to-monitor
  - https://github.com/SigmaHQ/sigma/blob/master/rules/cloud/azure/audit_logs/azure_guest_invite_failure.yml
author: Mark Morowczynski '@markmorow', Yochana Henderson, '@Yochana-H', Huntrule Team
date: 2022-08-10
tags:
  - attack.privilege-escalation
  - attack.initial-access
  - attack.persistence
  - attack.stealth
  - attack.t1078.004
logsource:
  product: azure
  service: auditlogs
detection:
  selection:
    properties.message: Invite external user
    Status: failure
  condition: selection
falsepositives:
  - A non malicious user is unaware of the proper process
level: medium
license: DRL-1.1
related:
  - id: 0b4b72e3-4c53-4d5b-b198-2c58cfef39a9
    type: derived

Convert

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