First access credential added to Application or Service Principal where no credential was present

AuditLogs
| where OperationName has ("Certificates and secrets management")
| where Result =~ "success"
| where tostring(InitiatedBy.user.userPrincipalName) has "@" or tostring(InitiatedBy.app.displayName) has "@"
| mv-apply TargetResource = TargetResources on 
  (
      where TargetResource.type =~ "Application"
      | extend targetDisplayName = tostring(TargetResource.displayName),
               targetId = tostring(TargetResource.id),
               targetType = tostring(TargetResource.type),
               keyEvents = TargetResource.modifiedProperties
  )
| mv-apply Property = keyEvents on 
  (
      where Property.displayName =~ "KeyDescription"
      | extend new_value_set = parse_json(tostring(Property.newValue)),
               old_value_set = parse_json(tostring(Property.oldValue))
  )
| where old_value_set == "[]"
| mv-expand new_value_set
| parse new_value_set with * "KeyIdentifier=" keyIdentifier:string ",KeyType=" keyType:string ",KeyUsage=" keyUsage:string ",DisplayName=" keyDisplayName:string "]" *
| where keyUsage =~ "Verify"
| mv-apply AdditionalDetail = AdditionalDetails on 
  (
      where AdditionalDetail.key =~ "User-Agent"
      | extend InitiatingUserAgent = tostring(AdditionalDetail.value)
  )
| project-away new_value_set, old_value_set, TargetResource, Property, AdditionalDetail
| extend InitiatingAppName = tostring(InitiatedBy.app.displayName)
| extend InitiatingAppServicePrincipalId = tostring(InitiatedBy.app.servicePrincipalId)
| extend InitiatingUserPrincipalName = tostring(InitiatedBy.user.userPrincipalName)
| extend InitiatingAadUserId = tostring(InitiatedBy.user.id)
| extend InitiatingIpAddress = tostring(iff(isnotempty(InitiatedBy.user.ipAddress), InitiatedBy.user.ipAddress, InitiatedBy.app.ipAddress))
| project-reorder TimeGenerated, OperationName, InitiatingUserPrincipalName, InitiatingAadUserId, InitiatingAppName, InitiatingAppServicePrincipalId, InitiatingIpAddress, InitiatingUserAgent, 
targetDisplayName, targetId, targetType, keyDisplayName, keyType, keyUsage, keyIdentifier, CorrelationId, TenantId
| extend Name = split(InitiatingUserPrincipalName, "@")[0], UPNSuffix = split(InitiatingUserPrincipalName, "@")[1]

triggerThreshold: 0
query: |
  AuditLogs
  | where OperationName has ("Certificates and secrets management")
  | where Result =~ "success"
  | where tostring(InitiatedBy.user.userPrincipalName) has "@" or tostring(InitiatedBy.app.displayName) has "@"
  | mv-apply TargetResource = TargetResources on 
    (
        where TargetResource.type =~ "Application"
        | extend targetDisplayName = tostring(TargetResource.displayName),
                 targetId = tostring(TargetResource.id),
                 targetType = tostring(TargetResource.type),
                 keyEvents = TargetResource.modifiedProperties
    )
  | mv-apply Property = keyEvents on 
    (
        where Property.displayName =~ "KeyDescription"
        | extend new_value_set = parse_json(tostring(Property.newValue)),
                 old_value_set = parse_json(tostring(Property.oldValue))
    )
  | where old_value_set == "[]"
  | mv-expand new_value_set
  | parse new_value_set with * "KeyIdentifier=" keyIdentifier:string ",KeyType=" keyType:string ",KeyUsage=" keyUsage:string ",DisplayName=" keyDisplayName:string "]" *
  | where keyUsage =~ "Verify"
  | mv-apply AdditionalDetail = AdditionalDetails on 
    (
        where AdditionalDetail.key =~ "User-Agent"
        | extend InitiatingUserAgent = tostring(AdditionalDetail.value)
    )
  | project-away new_value_set, old_value_set, TargetResource, Property, AdditionalDetail
  | extend InitiatingAppName = tostring(InitiatedBy.app.displayName)
  | extend InitiatingAppServicePrincipalId = tostring(InitiatedBy.app.servicePrincipalId)
  | extend InitiatingUserPrincipalName = tostring(InitiatedBy.user.userPrincipalName)
  | extend InitiatingAadUserId = tostring(InitiatedBy.user.id)
  | extend InitiatingIpAddress = tostring(iff(isnotempty(InitiatedBy.user.ipAddress), InitiatedBy.user.ipAddress, InitiatedBy.app.ipAddress))
  | project-reorder TimeGenerated, OperationName, InitiatingUserPrincipalName, InitiatingAadUserId, InitiatingAppName, InitiatingAppServicePrincipalId, InitiatingIpAddress, InitiatingUserAgent, 
  targetDisplayName, targetId, targetType, keyDisplayName, keyType, keyUsage, keyIdentifier, CorrelationId, TenantId
  | extend Name = split(InitiatingUserPrincipalName, "@")[0], UPNSuffix = split(InitiatingUserPrincipalName, "@")[1]  
relevantTechniques:
- T1550.001
tags:
- Solorigate
- NOBELIUM
triggerOperator: gt
entityMappings:
- entityType: Account
  fieldMappings:
  - identifier: FullName
    columnName: InitiatingUserPrincipalName
  - identifier: Name
    columnName: Name
  - identifier: UPNSuffix
    columnName: UPNSuffix
- entityType: Account
  fieldMappings:
  - identifier: AadUserId
    columnName: InitiatingAadUserId
- entityType: Account
  fieldMappings:
  - identifier: AadUserId
    columnName: InitiatingAppServicePrincipalId
- entityType: IP
  fieldMappings:
  - identifier: Address
    columnName: InitiatingIpAddress
- entityType: CloudApplication
  fieldMappings:
  - identifier: Name
    columnName: targetDisplayName
name: First access credential added to Application or Service Principal where no credential was present
version: 1.1.5
severity: High
requiredDataConnectors:
- connectorId: AzureActiveDirectory
  dataTypes:
  - AuditLogs
description: |
  'This will alert when an admin or app owner account adds a new credential to an Application or Service Principal where there was no previous verify KeyCredential associated.
  If a threat actor obtains access to an account with sufficient privileges and adds the alternate authentication material triggering this event, the threat actor can now authenticate as the Application or Service Principal using this credential.
  Additional information on OAuth Credential Grants can be found in RFC 6749 Section 4.4 or https://docs.microsoft.com/azure/active-directory/develop/v2-oauth2-client-creds-grant-flow
  For further information on AuditLogs please see https://docs.microsoft.com/azure/active-directory/reports-monitoring/reference-audit-activities.'  
queryPeriod: 1h
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft Entra ID/Analytic Rules/FirstAppOrServicePrincipalCredential.yaml
kind: Scheduled
queryFrequency: 1h
tactics:
- DefenseEvasion
status: Available
id: 2cfc3c6e-f424-4b88-9cc9-c89f482d016a