Entra ID Add User Outside PIM

// Copyright 2025 Google LLC. Licensed under Apache-2.0.

 rule entra_id_add_user_outside_pim {

  meta:
    author = "Google Cloud Security"
    description = "Adding users to roles is expected but if it occurs outside of PIM, validation should occur"
    rule_id = "mr_bc0a22e2-7ab1-4368-9408-3e6a5b666bec"
    rule_name = "Entra ID Add User Outside PIM"
    tactic = "TA0003"
    technique = "T1098.003"
    assumption = "The list entra_id_watchlist_roles or entra_id_watchlist_roles_guid is populated with role names, ie Exchange Administrator or 29232cdf-9323-42fd-ade2-1d097af3e4de, respectively"
    type = "alert"
    platform = "azure"
    data_source = "azure ad"
    severity = "Medium"
    priority = "Medium"

  events:
    $app.metadata.event_type = "USER_UNCATEGORIZED"
    $app.metadata.product_name = "Azure AD Directory Audit"
    $app.metadata.vendor_name = "Microsoft"
    $app.security_result.action = "ALLOW"
    $app.metadata.product_event_type = "Add member to role outside of PIM (permanent)" //triggered via PS API call
    //Can add watchlist of specific roles by name using the following commented out line
    //$app.target.resource.name in %entra_id_watchlist_roles
    //Can add watchlist of specific roles by guid using the following commented out line
    //$app.target.resource.attribute.labels["TemplateId"] in %entra_id_watchlist_roles_guid
    $app.principal.user.userid = $user

  match:
    $user over 5m

  outcome:
    $risk_score = 65
    $event_count = count_distinct($app.metadata.id)
    $assigned_role = array_distinct($app.target.resource.name)
    $assigned_role_guid = array_distinct($app.target.resource.attribute.labels["TemplateId"])
    $network_session = array_distinct($app.network.session_id)
    $userid_making_modification = array_distinct($app.principal.user.userid)
    $principal_user_email_addresses = array_distinct($app.principal.user.email_addresses)
    $modified_userid = array_distinct($app.target.user.email_addresses)

  condition:
    $app
}