Detection rules › YARA-L

Okta Phishing Detection With Fastpass Origin Check

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

Okta provides a platform detection for when a user enrolled in FastPass fails to authenticate via a real-time AiTM phishing proxy.

MITRE ATT&CK coverage

TacticTechniques
Initial AccessT1566 Phishing

References

Event coverage

Rules detecting the same action

Other rules on this platform that filter on the same API call or operation.

Rule body yaral

/*
 * Copyright 2023 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

rule okta_phishing_detection_with_fastpass_origin_check {

  meta:
    author = "Google Cloud Security"
    description = "Okta provides a platform detection for when a user enrolled in FastPass fails to authenticate via a real-time AiTM phishing proxy."
    rule_id = "mr_07d1a26d-1132-4228-bd49-c8dd899c7792"
    rule_name = "Okta Phishing Detection With Fastpass Origin Check"
    reference = "https://sec.okta.com/fastpassphishingdetection"
    mitre_attack_tactic = "Initial Access"
    mitre_attack_technique = "Phishing"
    mitre_attack_url = "https://attack.mitre.org/techniques/T1566/"
    mitre_attack_version = "v13.1"
    type = "Alert"
    data_source = "Okta"
    severity = "Medium"
    priority = "Medium"

  events:
    $login.metadata.product_name = "Okta"
    $login.metadata.vendor_name = "Okta"
    $login.metadata.event_type = "USER_LOGIN"
    $login.metadata.product_event_type = "user.authentication.auth_via_mfa"
    $login.security_result.action = "BLOCK"
    $login.security_result.category_details = "FastPass declined phishing attempt"
    $login.target.user.userid = $userid

  match:
    $userid over 1h

  outcome:
    $risk_score = max(35)
    $mitre_attack_tactic = "Initial Access"
    $mitre_attack_technique = "Phishing"
    $target_user_agent = array_distinct($login.network.http.user_agent)
    $principal_ip = array_distinct($login.principal.ip)
    $principal_ip_country = array_distinct($login.principal.ip_geo_artifact.location.country_or_region)
    $principal_ip_state = array_distinct($login.principal.ip_geo_artifact.location.state)
    $principal_ip_city = array_distinct($login.principal.location.city)
    $principal_user_email_addresses = array_distinct ($login.principal.user.email_addresses)
    $security_result_summary = array_distinct($login.security_result.summary)
    $target_user_email_addresses = array_distinct($login.target.user.email_addresses)
    $target_user_userid = array_distinct($login.target.user.userid)
    $security_result_risk_reason = array_distinct($login.security_result.detection_fields["Risk Reasons"])

  condition:
    $login
}

Detection logic

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

Events

$login USER_LOGIN

  • metadata.product_event_type = "user.authentication.auth_via_mfa"
  • security_result.action = "BLOCK"
  • security_result.category_details = "FastPass declined phishing attempt"

Correlation

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

Outcome

Fields the detection emits on a match. $risk_score drives alerting; Chronicle surfaces the rest on the detection.

FieldExpression
risk_scoremax(35)
target_user_agentarray_distinct($login.network.http.user_agent)
principal_iparray_distinct($login.principal.ip)
principal_ip_countryarray_distinct($login.principal.ip_geo_artifact.location.country_or_region)
principal_ip_statearray_distinct($login.principal.ip_geo_artifact.location.state)
principal_ip_cityarray_distinct($login.principal.location.city)
principal_user_email_addressesarray_distinct ($login.principal.user.email_addresses)
security_result_summaryarray_distinct($login.security_result.summary)
target_user_email_addressesarray_distinct($login.target.user.email_addresses)
target_user_useridarray_distinct($login.target.user.userid)
security_result_risk_reasonarray_distinct($login.security_result.detection_fields["Risk Reasons"])