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

id: b6988c32-4f3b-4a45-8313-b46b33061a74
name: NRT First access credential added to Application or Service Principal where no credential was present
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.'
severity: Medium
requiredDataConnectors:
  - connectorId: AzureActiveDirectory
    dataTypes:
      - AuditLogs
tactics:
  - DefenseEvasion
relevantTechniques:
  - T1550.001
tags:
  - Solorigate
  - NOBELIUM
query: |
  AuditLogs
  | where OperationName has_any ("Add service principal", "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 UserAgent = tostring(AdditionalDetail.value)
    )
  | 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))
  //| where targetType =~ "Application" // or targetType =~ "ServicePrincipal"
  | project-away new_value_set, old_value_set
  | project-reorder TimeGenerated, OperationName, InitiatingUserPrincipalName, InitiatingAadUserId, InitiatingAppName, InitiatingAppServicePrincipalId, InitiatingIpAddress, UserAgent, targetDisplayName, targetId, targetType, keyDisplayName, keyType, keyUsage, keyIdentifier, CorrelationId, TenantId
  | extend InitiatedByName = tostring(split(InitiatingUserPrincipalName,'@',0)[0]), InitiatedByUPNSuffix = tostring(split(InitiatingUserPrincipalName,'@',1)[0])
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: InitiatingUserPrincipalName
      - identifier: Name
        columnName: InitiatedByName
      - identifier: UPNSuffix
        columnName: InitiatedByUPNSuffix
  - entityType: Account
    fieldMappings:
      - identifier: AadUserId
        columnName: InitiatingAadUserId
  - entityType: Account
    fieldMappings:
      - identifier: AadUserId
        columnName: InitiatingAppServicePrincipalId
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: InitiatingIpAddress
version: 1.0.6
kind: NRT
metadata:
source:
    kind: Community
author:
    name: Samik Roy
support:
    tier: Community
categories:
    domains: [ "Security - Others", "Identity" ]
threatAnalysisTactics: [ "DefenseEvasion" ]
threatAnalysisTechniques: [ "T1550.001" ]