Windows Multiple Users Remotely Failed To Authenticate From Host

name: Windows Multiple Users Remotely Failed To Authenticate From Host
id: 80f9d53e-9ca1-11eb-b0d6-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 identifies a source host failing to authenticate against a remote host with 30 unique users. It leverages Windows Event 4625 with Logon Type 3, indicating remote authentication attempts. This behavior is significant as it may indicate a Password Spraying attack, where an adversary attempts to gain initial access or elevate privileges in an Active Directory environment. If confirmed malicious, this activity could lead to unauthorized access, privilege escalation, and potential compromise of sensitive information. This detection is crucial for real-time security monitoring and threat hunting.
data_source:
    - Windows Event Log Security 4625
search: |-
    `wineventlog_security` EventCode=4625 Logon_Type=3 IpAddress!="-"
      | 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, IpAddress, Computer,
           action, app, authentication_method,
           signature, signature_id
      | rename Computer as dest
      | where unique_accounts > 30
      | `windows_multiple_users_remotely_failed_to_authenticate_from_host_filter`
how_to_implement: To successfully implement this search, you need to be ingesting Windows Event Logs from domain controllers as as 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 host failing to authenticate with multiple valid users against a remote host is not a common behavior for legitimate systems. Possible false positive scenarios include but are not limited to vulnerability scanners, remote administration tools, missconfigyred systems, etc.
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 on $dest$
    entity:
        field: dest
        type: system
        score: 50
analytic_story:
    - Active Directory Password Spraying
    - Volt Typhoon
asset_type: Endpoint
mitre_attack_id:
    - T1110.003
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint