Windows Multiple Users Failed To Authenticate From Process

name: Windows Multiple Users Failed To Authenticate From Process
id: 9015385a-9c84-11eb-bef2-acde48001122
version: 13
creation_date: '2021-04-14'
modification_date: '2026-05-13'
author: Mauricio Velazco, Splunk
status: production
type: TTP
description: The following analytic detects a source process failing to authenticate with 30 unique users, indicating a potential Password Spraying attack. It leverages Windows Event 4625 with Logon Type 2, collected from domain controllers, member servers, and workstations. This activity is significant as it may represent an adversary attempting to gain initial access or elevate privileges within an Active Directory environment. If confirmed malicious, this could lead to unauthorized access, privilege escalation, or further compromise of the network, posing a severe security risk.
data_source:
    - Windows Event Log Security 4625
search: |-
    `wineventlog_security` EventCode=4625 Logon_Type=2 ProcessName!="-"
      | bucket span=5m _time
      | stats dc(TargetUserName) AS unique_accounts values(TargetUserName) as tried_accounts values(dest) as dest values(src) as src values(user) as user
        BY _time, ProcessName, SubjectUserName,
           Computer, action, app,
           authentication_method, signature, signature_id
      | rename Computer as dest
      | where unique_accounts > 30
      | `windows_multiple_users_failed_to_authenticate_from_process_filter`
how_to_implement: To successfully implement this search, you need to be ingesting Windows Event Logs from domain controllers aas well as member servers and workstations. The Advanced Security Audit policy setting `Audit Logon` within `Logon/Logoff` needs to be enabled.
known_false_positives: A process failing to authenticate with multiple users is not a common behavior for legitimate user sessions. Possible false positive scenarios include but are not limited to vulnerability scanners and missconfigured systems.
references:
    - https://attack.mitre.org/techniques/T1110/003/
    - https://docs.microsoft.com/en-us/windows/security/threat-protection/auditing/event-4625
    - https://www.ultimatewindowssecurity.com/securitylog/encyclopedia/event.aspx?eventID=4625
    - https://docs.microsoft.com/en-us/windows/security/threat-protection/auditing/basic-audit-logon-events
finding:
    title: Potential password spraying attack from $dest$
    entity:
        field: dest
        type: system
        score: 50
analytic_story:
    - Active Directory Password Spraying
    - Insider Threat
    - Volt Typhoon
asset_type: Endpoint
mitre_attack_id:
    - T1110.003
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint