Detection rules › Splunk

Windows Multiple Disabled Users Failed To Authenticate Wth Kerberos

Status
production
Severity
medium
Group by
_time, src_ip
Author
Mauricio Velazco, Splunk
Source
github.com/splunk/security_content

The following analytic detects a single source endpoint failing to authenticate with 30 unique disabled domain users using the Kerberos protocol within 5 minutes. It leverages Windows Security Event 4768, focusing on failure code 0x12, indicating revoked credentials. This activity is significant as it may indicate a Password Spraying attack targeting disabled accounts, a tactic used by adversaries to gain initial access or elevate privileges. If confirmed malicious, this could lead to unauthorized access or privilege escalation within the Active Directory environment, posing a severe security risk.

MITRE ATT&CK coverage

TacticTechniques
Credential AccessT1110.003 Brute Force: Password Spraying

Event coverage

Rule body splunk

name: Windows Multiple Disabled Users Failed To Authenticate Wth Kerberos
id: 98f22d82-9d62-11eb-9fcf-acde48001122
version: 12
creation_date: '2021-04-14'
modification_date: '2026-05-13'
author: Mauricio Velazco, Splunk
status: production
type: TTP
description: The following analytic detects a single source endpoint failing to authenticate with 30 unique disabled domain users using the Kerberos protocol within 5 minutes. It leverages Windows Security Event 4768, focusing on failure code `0x12`, indicating revoked credentials. This activity is significant as it may indicate a Password Spraying attack targeting disabled accounts, a tactic used by adversaries to gain initial access or elevate privileges. If confirmed malicious, this could lead to unauthorized access or privilege escalation within the Active Directory environment, posing a severe security risk.
data_source:
    - Windows Event Log Security 4768
search: |-
    `wineventlog_security` EventCode=4768 TargetUserName!=*$ Status=0x12
      | bucket span=5m _time
      | stats dc(TargetUserName) AS unique_accounts values(TargetUserName) as user values(dest) as dest
        BY _time, IpAddress
      | where unique_accounts > 30
      | `windows_multiple_disabled_users_failed_to_authenticate_wth_kerberos_filter`
how_to_implement: To successfully implement this search, you need to be ingesting Domain Controller and Kerberos events. The Advanced Security Audit policy setting `Audit Kerberos Authentication Service` within `Account Logon` needs to be enabled.
known_false_positives: A host failing to authenticate with multiple disabled domain users is not a common behavior for legitimate systems. Possible false positive scenarios include but are not limited to vulnerability scanners, multi-user systems missconfigured systems.
references:
    - https://attack.mitre.org/techniques/T1110/003/
drilldown_searches:
    - name: View the detection results for - "$user$"
      search: '%original_detection_search% | search  user = "$user$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$user$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: 7d
      latest_offset: "0"
finding:
    title: Potential Kerberos based password spraying attack from $IpAddress$
    entity:
        field: user
        type: user
        score: 50
threat_objects:
    - field: IpAddress
      type: ip_address
analytic_story:
    - Active Directory Password Spraying
    - Active Directory Kerberos Attacks
    - Volt Typhoon
asset_type: Endpoint
mitre_attack_id:
    - T1110.003
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
    - attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1110.003/purplesharp_disabled_users_kerberos_xml/windows-security.log
          source: XmlWinEventLog:Security
          sourcetype: XmlWinEventLog
      name: True Positive Test
      test_type: unit

Stages and Predicates

Stage 1: search

`wineventlog_security` EventCode=4768 TargetUserName!=*$ Status=0x12

Stage 2: bucket

| bucket span=5m _time

Stage 3: stats

| stats dc(TargetUserName) AS unique_accounts values(TargetUserName) as user values(dest) as dest
    BY _time, IpAddress

Stage 4: where

| where unique_accounts > 30

Stage 5: search

| `windows_multiple_disabled_users_failed_to_authenticate_wth_kerberos_filter`

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
EventCodeeq
  • 4768 corpus 13 (splunk 11, kusto 2)
Statuseq
  • 0x12 corpus 2 (splunk 2)
TargetUserNamene
  • *$ corpus 14 (splunk 14)
unique_accountsgt
  • 30 corpus 9 (splunk 9)