Detection rules › Sigma
Use of Legacy Authentication Protocols
Alert on when legacy authentication has been used on an account
Known false positives
- User has been put in acception group so they can use legacy authentication
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Initial Access | |
| Persistence | |
| Privilege Escalation | |
| Stealth | |
| Credential Access |
Telemetry coverage
| Platform | Record / event type |
|---|---|
| Entra ID | SigninLogs sign-in event: Sign-in from a named client app (legacy authentication signal) |
Rule body
title: Use of Legacy Authentication Protocols
id: 60f6535a-760f-42a9-be3f-c9a0a025906e
status: test
description: Alert on when legacy authentication has been used on an account
references:
- https://learn.microsoft.com/en-gb/entra/architecture/security-operations-privileged-accounts
author: Yochana Henderson, '@Yochana-H'
date: 2022-06-17
tags:
- attack.privilege-escalation
- attack.persistence
- attack.initial-access
- attack.credential-access
- attack.stealth
- attack.t1078.004
- attack.t1110
logsource:
product: azure
service: signinlogs
detection:
selection:
ActivityDetails: Sign-ins
ClientApp:
- Other client
- IMAP
- POP3
- MAPI
- SMTP
- Exchange ActiveSync
- Exchange Web Services
Username: 'UPN'
condition: selection
falsepositives:
- User has been put in acception group so they can use legacy authentication
level: high
Stages and Predicates
Stage 0: condition
selectionStage 1: selection
selection:
ActivityDetails: Sign-ins
ClientApp:
- Other client
- IMAP
- POP3
- MAPI
- SMTP
- Exchange ActiveSync
- Exchange Web Services
Username: 'UPN'
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
ActivityDetails | eq |
| field:"ActivityDetails" kind:eq value:"Sign-ins" |
ClientApp | eq |
| field:"ClientApp" kind:eq |
Username | eq |
| field:"user" kind:eq value:"UPN" |