Azure Audit Logs: UserType updated from Guest to Member

Alerts when an Azure user’s UserType is updated from Guest to Member, indicating potential privilege elevation.

FreeReviewedSigma · Medium · v5

Product: azure
Service: auditlogs
Author: MikeDuddington, '@dudders1' (SigmaHQ), DRL 1.1
Published: 2022-06-30
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 matches Azure audit log events where a user management operation updates a user’s UserType from "Guest" to "Member". Such a change can enable additional access or privileges, making it relevant for detecting potential elevation of privilege or stealthy permission gains. It relies on UserManagement “Update user” events with a message indicating the old and new UserType values.

Reporting behind it

Related detections9 linkedT1078.004 — drag to rearrange

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Suspicious AWS Federated Console Login From Programmatic Credentials

Suspicious M365 Legacy Authentication via BAV2ROPC Client via m365

Suspicious STS AssumeRole With Exfil Session Name via CloudTrail (via cloudtrail)

Suspicious AWS Console Login Without MFA

Suspicious Cloud Sign-In From an Anonymizer or High-Risk Session (via signinlogs)

Azure Audit Logs: UserType updated from Guest to Member

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-audit-logs-user-type-changed-from-guest-to-member-8dee7a0d

title: "Azure Audit Logs: UserType updated from Guest to Member"
id: 29ce7a7e-14eb-40f6-b594-3e9464e317f8
status: test
description: This rule matches Azure audit log events where a user management operation updates a user’s UserType from "Guest" to "Member". Such a change can enable additional access or privileges, making it relevant for detecting potential elevation of privilege or stealthy permission gains. It relies on UserManagement “Update user” events with a message indicating the old and new UserType values.
references:
  - https://learn.microsoft.com/en-gb/entra/architecture/security-operations-user-accounts#monitoring-external-user-sign-ins
  - https://github.com/SigmaHQ/sigma/blob/master/rules/cloud/azure/audit_logs/azure_guest_to_member.yml
author: MikeDuddington, '@dudders1', Huntrule Team
date: 2022-06-30
tags:
  - attack.persistence
  - attack.privilege-escalation
  - attack.initial-access
  - attack.stealth
  - attack.t1078.004
logsource:
  product: azure
  service: auditlogs
detection:
  selection:
    Category: UserManagement
    OperationName: Update user
    properties.message: '"displayName":"UserType","oldValue":"[\"Guest\"]","newValue":"[\"Member\"]"'
  condition: selection
falsepositives:
  - If this was approved by System Administrator.
level: medium
license: DRL-1.1
related:
  - id: 8dee7a0d-43fd-4b3c-8cd1-605e189d195e
    type: derived

Convert

This rule as a query you can run. Uses no unlock credit.

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