sap_user_creates_and_uses_new_user

rule sap_user_creates_and_uses_new_user {

  meta:
    author = "Google Cloud Security"
    description = "Detects a user creating a new account (AU7) and subsequently logging into it (AU1, AU5) from the same terminal within a short timeframe."
    severity = "Critical"
    tactic = "TA0003"
    technique = "T1136"

  events:
    $create.metadata.log_type = "SAP_SECURITY_AUDIT"
    $create.additional.fields["msg_1"] = "AU7"
    $creator = $create.principal.user.userid

    $login.metadata.log_type = "SAP_SECURITY_AUDIT"
    $login.additional.fields["msg_1"] = /^AU1$|^AU5$/

    //join
    $new_user = $create.additional.fields["param1_1"]
    $new_user = $login.principal.user.userid
    $terminal = $create.principal.ip
    $terminal = $login.principal.ip
    $sid = $create.target.application
    $sid = $login.target.application

    //sequence
    $create.metadata.event_timestamp.seconds <= $login.metadata.event_timestamp.seconds

    //exclusions
    not $create.principal.user.userid in %sap_admin_users.user

  match:
    $terminal, $sid over 30m

  outcome:
    $risk_score = 85
    $creating_user = array_distinct($creator)
    $created_user = array_distinct($new_user)
    $description = array_distinct($create.metadata.description)

  condition:
    $create and $login
}