High-privilege application role assigned to service principal

id: 840c673e-a712-49eb-a6a9-6759d5259c4b
name: High-privilege application role assigned to service principal
description: |
  Identifies application role assignments to service principals granting high-risk
  permissions such as Mail.ReadWrite, Directory.ReadWrite.All, or
  RoleManagement.ReadWrite.Directory, which provide tenant-wide API access
  without user context.
requiredDataConnectors:
  - connectorId: AzureActiveDirectory
    dataTypes:
      - AuditLogs
tactics:
  - Persistence
  - CredentialAccess
relevantTechniques:
  - T1098.003
  - T1528
query: |
  let timeframe = 1d;
  let HighRiskRoles = dynamic([
      "Mail.ReadWrite",
      "Mail.Send",
      "Files.ReadWrite.All",
      "Directory.ReadWrite.All",
      "RoleManagement.ReadWrite.Directory",
      "Application.ReadWrite.All",
      "AppRoleAssignment.ReadWrite.All",
      "User.ReadWrite.All",
      "full_access_as_app"
  ]);
  AuditLogs
  | where TimeGenerated >= ago(timeframe)
  | where OperationName =~ "Add app role assignment to service principal"
  | where Result =~ "success"
  | extend ActorUpn = tostring(InitiatedBy.user.userPrincipalName)
  | extend ActorApp = tostring(InitiatedBy.app.displayName)
  | extend Actor    = iff(isnotempty(ActorUpn), ActorUpn, ActorApp)
  | extend ActorIp  = iff(
        isnotempty(tostring(InitiatedBy.user.ipAddress)),
        tostring(InitiatedBy.user.ipAddress),
        tostring(InitiatedBy.app.ipAddress))
  | extend TargetSpName = tostring(TargetResources[0].displayName)
  | extend TargetSpId   = tostring(TargetResources[0].id)
  | mv-expand ModProp = TargetResources[0].modifiedProperties
  | where tostring(ModProp.displayName) =~ "AppRole.Value"
  | extend AppRoleName = trim('"', tostring(ModProp.newValue))
  | where AppRoleName in~ (HighRiskRoles)
  | extend AccountName      = iff(Actor has "@", tostring(split(Actor, "@")[0]), Actor)
  | extend AccountUPNSuffix = iff(Actor has "@", tostring(split(Actor, "@")[1]), "")
  | project TimeGenerated, Actor, AccountName, AccountUPNSuffix, ActorIp,
            TargetSpName, TargetSpId, AppRoleName, CorrelationId
  | sort by TimeGenerated desc
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: Actor
      - identifier: Name
        columnName: AccountName
      - identifier: UPNSuffix
        columnName: AccountUPNSuffix
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: ActorIp
version: 1.0.0
metadata:
    source:
        kind: Community
    author:
        name: descambiado
    support:
        tier: Community
    categories:
        domains: [ "Security - Threat Protection", "Identity" ]