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Sigma rules for CVE-2021-42306

2 rules · scoped to cve · back to CVE-2021-42306

Direct rules mention this entity in their title or description. Related rules cover the techniques this entity is known to use.

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Detection rules

2 of 2

direct medium

Azure Active Directory Hybrid Health AD FS New Server

This detection uses azureactivity logs (Administrative category) to identify the creation or update of a server instance in an Azure AD Hybrid health AD FS service. A threat actor can create a new AD Health ADFS service and create a fake server instance to spoof AD FS signing logs. There is no need to compromise an on-prem AD FS server. This can be done programmatically via HTTP requests to Azure.

status test author Roberto Rodriguez (Cyb3rWard0g), OTR (Open Threat Research), MSTIC id 288a39fc-4914-4831-9ada-270e9dc12cb4 license Sigma · DRL-1.1

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title: Azure Active Directory Hybrid Health AD FS New Server
id: 288a39fc-4914-4831-9ada-270e9dc12cb4
status: test
description: |
    This detection uses azureactivity logs (Administrative category) to identify the creation or update of a server instance in an Azure AD Hybrid health AD FS service.
    A threat actor can create a new AD Health ADFS service and create a fake server instance to spoof AD FS signing logs. There is no need to compromise an on-prem AD FS server.
    This can be done programmatically via HTTP requests to Azure.
references:
    - https://o365blog.com/post/hybridhealthagent/
author: Roberto Rodriguez (Cyb3rWard0g), OTR (Open Threat Research), MSTIC
date: 2021-08-26
modified: 2023-10-11
tags:
    - attack.defense-impairment
    - attack.t1578
logsource:
    product: azure
    service: activitylogs
detection:
    selection:
        CategoryValue: 'Administrative'
        ResourceProviderValue: 'Microsoft.ADHybridHealthService'
        ResourceId|contains: 'AdFederationService'
        OperationNameValue: 'Microsoft.ADHybridHealthService/services/servicemembers/action'
    condition: selection
falsepositives:
    - Legitimate AD FS servers added to an AAD Health AD FS service instance
level: medium

direct medium

Azure Active Directory Hybrid Health AD FS Service Delete

This detection uses azureactivity logs (Administrative category) to identify the deletion of an Azure AD Hybrid health AD FS service instance in a tenant. A threat actor can create a new AD Health ADFS service and create a fake server to spoof AD FS signing logs. The health AD FS service can then be deleted after it is not longer needed via HTTP requests to Azure.

status test author Roberto Rodriguez (Cyb3rWard0g), OTR (Open Threat Research), MSTIC id 48739819-8230-4ee3-a8ea-e0289d1fb0ff license Sigma · DRL-1.1

view Sigma YAML

title: Azure Active Directory Hybrid Health AD FS Service Delete
id: 48739819-8230-4ee3-a8ea-e0289d1fb0ff
status: test
description: |
    This detection uses azureactivity logs (Administrative category) to identify the deletion of an Azure AD Hybrid health AD FS service instance in a tenant.
    A threat actor can create a new AD Health ADFS service and create a fake server to spoof AD FS signing logs.
    The health AD FS service can then be deleted after it is not longer needed via HTTP requests to Azure.
references:
    - https://o365blog.com/post/hybridhealthagent/
author: Roberto Rodriguez (Cyb3rWard0g), OTR (Open Threat Research), MSTIC
date: 2021-08-26
modified: 2023-10-11
tags:
    - attack.defense-impairment
    - attack.t1578.003
logsource:
    product: azure
    service: activitylogs
detection:
    selection:
        CategoryValue: 'Administrative'
        ResourceProviderValue: 'Microsoft.ADHybridHealthService'
        ResourceId|contains: 'AdFederationService'
        OperationNameValue: 'Microsoft.ADHybridHealthService/services/delete'
    condition: selection
falsepositives:
    - Legitimate AAD Health AD FS service instances being deleted in a tenant
level: medium

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