Okta ThreatInsight Targeted Bruteforce Attack

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

Okta ThreatInsight detects access requests from known malicious IPs targeting a specific org.

MITRE ATT&CK coverage

Tactic	Techniques
Credential Access	`T1110` Brute Force

References

https://help.okta.com/en-us/Content/Topics/Security/threat-insight/configure-threatinsight-system-log.htm

Telemetry coverage

Platform	Record / event type
Okta	System Log event type `security.attack.start`: Org under attack per Threat Insight

Rules detecting the same action

These rules filter on the same operation.

Device Registration from Malicious IP (Kusto)

Rule body

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

rule okta_threatinsight_targeted_brute_force_attack {

  meta:
    author = "Google Cloud Security"
    description = "Okta ThreatInsight detects access requests from known malicious IPs targeting a specific org."
    rule_id = "mr_ce576f12-ee6d-4282-9f7b-f955af183eb7"
    rule_name = "Okta ThreatInsight Targeted Bruteforce Attack"
    reference = "https://help.okta.com/en-us/Content/Topics/Security/threat-insight/configure-threatinsight-system-log.htm"
    mitre_attack_tactic = "Credential Access"
    mitre_attack_technique = "Brute Force"
    mitre_attack_url = "https://attack.mitre.org/techniques/T1110/"
    mitre_attack_version = "v13.1"
    type = "Alert"
    data_source = "Okta"
    severity = "Medium"
    priority = "Medium"

  events:
    $bruteforce.metadata.product_name = "Okta"
    $bruteforce.metadata.vendor_name = "Okta"
    $bruteforce.metadata.event_type = "USER_UNCATEGORIZED"
    $bruteforce.metadata.product_event_type = "security.attack.start"
    $bruteforce.principal.user.userid = $userid

  match:
    $userid over 1h

  outcome:
    $risk_score = max(35)
    $mitre_attack_tactic = "Credential Access"
    $mitre_attack_technique = "Brute Force"
    $principal_user_userid = array_distinct($bruteforce.principal.user.userid)
    $principal_user_email_addresses = array_distinct($bruteforce.principal.user.email_addresses)
    $security_result_summary = array_distinct($bruteforce.security_result.summary)
    $security_result_severity = array_distinct($bruteforce.security_result.severity)

  condition:
    $bruteforce
}

YARA-L rule structure

Condition

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

Events

`$bruteforce` `USER_UNCATEGORIZED`

metadata.product_event_type = "security.attack.start"

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.

Field	Expression
`risk_score`	`max(35)`
`principal_user_userid`	`array_distinct($bruteforce.principal.user.userid)`
`principal_user_email_addresses`	`array_distinct($bruteforce.principal.user.email_addresses)`
`security_result_summary`	`array_distinct($bruteforce.security_result.summary)`
`security_result_severity`	`array_distinct($bruteforce.security_result.severity)`