Detection rules › YARA-L

Okta User Account Lockout

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

Detects when a user's account is locked out or a user account has reached the lockout limit.

MITRE ATT&CK coverage

TacticTechniques
Initial AccessT1078 Valid Accounts
PersistenceT1078 Valid Accounts
Privilege EscalationT1078 Valid Accounts
StealthT1078 Valid Accounts

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_user_account_lockout {

  meta:
    author = "Google Cloud Security"
    description = "Detects when a user's account is locked out or a user account has reached the lockout limit."
    rule_id = "mr_b7d1d908-77db-4217-a170-44e0423c7fbe"
    rule_name = "Okta User Account Lockout"
    reference = "https://www.okta.com/resources/whitepaper/how-adaptive-mfa-helps-mitigate-brute-force-attacks/"
    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 = "Okta"
    severity = "Medium"
    priority = "Medium"

  events:
    $login.metadata.product_name = "Okta"
    $login.metadata.vendor_name = "Okta"
    (
        $login.metadata.product_event_type = "user.account.lock.limit" or
        $login.metadata.product_event_type = "user.account.lock"
    )
    $login.security_result.action = "BLOCK"
    $login.principal.user.userid = $userid

  match:
    $userid over 1h

  outcome:
    $risk_score = max(35)
    $mitre_attack_tactic = "Defense Evasion, Persistence, Privilege Escalation, Initial Access"
    $mitre_attack_technique = "Valid Accounts"
    $target_user_agent = array_distinct($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)
    $security_result_category_details = array_distinct($login.security_result.category_details)

  condition:
    $login
}

Detection logic

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

Events

$login

  • metadata.product_event_type = "user.account.lock.limit" or "user.account.lock"
  • security_result.action = "BLOCK"

Correlation

Match key
$userid (principal.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($login.security_result.summary)
security_result_category_detailsarray_distinct($login.security_result.category_details)