Detection rules › YARA-L

Google Workspace SAML IDP Configuration Change

Severity
high
Type
Alert
Time window
1h
Match by
userid
Author
Google Cloud Security
Source
github.com/chronicle/detection-rules

Identifies SAML provider configuration changes in Google Workspace. Security teams can monitor for changes to SAML provider configuration that may weaken the organization's security posture.

MITRE ATT&CK coverage

TacticTechniques
Initial Access
Persistence
Privilege Escalation
Stealth

Telemetry coverage

Rule body

// Copyright 2023 Google LLC. Licensed under Apache-2.0.

rule google_workspace_saml_idp_configuration_change {

  meta:
    author = "Google Cloud Security"
    description = "Identifies SAML provider configuration changes in Google Workspace. Security teams can monitor for changes to SAML provider configuration that may weaken the organization's security posture."
    rule_id = "mr_1a321683-9c52-4928-a654-e0677df97c09"
    rule_name = "Google Workspace SAML IDP Configuration Change"
    mitre_attack_tactic = "Defense Evasion, Persistence, Privilege Escalation, Initial Access"
    mitre_attack_technique = "Valid Accounts"
    mitre_attack_url = "https://attack.mitre.org/techniques/T1078/"
    mitre_attack_version = "v13.1"
    type = "Alert"
    data_source = "Workspace Activity"
    severity = "High"
    priority = "High"

  events:
    $ws.metadata.vendor_name = "Google Workspace"
    $ws.metadata.product_name = "admin"
    $ws.security_result.category_details = "SAML2_SERVICE_PROVIDER_CONFIG_SETTINGS"
    $ws.metadata.product_event_type = /SAML2_SERVICE_PROVIDER_CONFIG/
    $ws.principal.user.userid = $userid

  match:
    $userid over 1h

  outcome:
    $risk_score = max(75)
    $mitre_attack_tactic = "Defense Evasion, Persistence, Privilege Escalation, Initial Access"
    $mitre_attack_technique = "Valid Accounts"
    $mitre_attack_technique_id = "T1078"
    $event_count = count_distinct($ws.metadata.id)
    $principal_ip = array_distinct($ws.principal.ip)
    $principal_country = array_distinct($ws.principal.ip_geo_artifact.location.country_or_region)
    $principal_state = array_distinct($ws.principal.ip_geo_artifact.location.state)
    $principal_user_emails = array_distinct($ws.principal.user.email_addresses)
    $principal_user_id = array_distinct($ws.principal.user.userid)
    $saml_entity_id = array_distinct($ws.about.labels["saml2_service_provider_entity_id"])
    $saml_name = array_distinct($ws.about.labels["saml2_service_provider_name"])
    $product_event_type = array_distinct($ws.metadata.product_event_type)

  condition:
    $ws
}

YARA-L rule structure

Condition

Fires when at least one $ws event in the 1h window.

Events

$ws

  • security_result.category_details = "SAML2_SERVICE_PROVIDER_CONFIG_SETTINGS"
  • metadata.product_event_type matches "SAML2_SERVICE_PROVIDER_CONFIG"

Match and correlation

Match key
$userid (principal.user.userid)
Within
1h

Outcome

Outcome variables add context to a detection. When the rule generates an alert, $risk_score is displayed with it.

FieldExpression
risk_scoremax(75)
event_countcount_distinct($ws.metadata.id)
principal_iparray_distinct($ws.principal.ip)
principal_countryarray_distinct($ws.principal.ip_geo_artifact.location.country_or_region)
principal_statearray_distinct($ws.principal.ip_geo_artifact.location.state)
principal_user_emailsarray_distinct($ws.principal.user.email_addresses)
principal_user_idarray_distinct($ws.principal.user.userid)
saml_entity_idarray_distinct($ws.about.labels["saml2_service_provider_entity_id"])
saml_namearray_distinct($ws.about.labels["saml2_service_provider_name"])
product_event_typearray_distinct($ws.metadata.product_event_type)