Windows Security: Suspicious Failed Logons Using Uncommon Status/Substatus Codes

Alerts on Windows failed logons (4625/4776) with specific restricted-status codes indicating potential account tampering or access probing.

FreeReviewedSigma · Medium · v2

Product: windows
Service: security
Author: Florian Roth (Nextron Systems) (SigmaHQ), DRL 1.1
Published: 2017-02-19
Updated: 2026-07-31

Analysis Detection

ATT&CK techniques

Initial Access → Defense Evasion

Recon
Resource Dev
Initial Access
- T1078Valid Accounts
Execution
Persistence
- T1078Valid Accounts
Priv Esc
- T1078Valid Accounts
Defense Evasion
- T1078Valid Accounts
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule identifies Windows Security audit events for failed logons using specific, uncommon Status and SubStatus codes that indicate logon restrictions or trust/authentication failures. Such patterns can reflect account tampering attempts, misconfigured access controls, or probing of disabled/restricted accounts to evade defenses or validate authorization boundaries. It relies on Windows Security log telemetry for EventID 4625 and 4776, including Status and SubStatus fields, while excluding non-user activity via SubjectUserSid S-1-0-0.

Reporting behind it

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Windows Security: Suspicious Failed Logons Using Uncommon Status/Substatus Codes

Pivot detection · T1078 · 9 related

Changelog

v2
Candidate ingested via manual entry.2026-07-31
v1
No changelog recorded for this version.2026-07-30

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

windows-failed-logons-with-suspicious-status-substatus-codes-4625-4776-9eb99343

title: "Windows Security: Suspicious Failed Logons Using Uncommon Status/Substatus Codes"
id: fe163d05-6f0d-449f-b09b-6cadcfb13a2a
status: test
description: This rule identifies Windows Security audit events for failed logons using specific, uncommon Status and SubStatus codes that indicate logon restrictions or trust/authentication failures. Such patterns can reflect account tampering attempts, misconfigured access controls, or probing of disabled/restricted accounts to evade defenses or validate authorization boundaries. It relies on Windows Security log telemetry for EventID 4625 and 4776, including Status and SubStatus fields, while excluding non-user activity via SubjectUserSid S-1-0-0.
references:
  - https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-10/security/threat-protection/auditing/event-4625
  - https://twitter.com/SBousseaden/status/1101431884540710913
  - https://github.com/SigmaHQ/sigma/blob/master/rules/windows/builtin/security/win_security_susp_failed_logon_reasons.yml
author: Florian Roth (Nextron Systems), Huntrule Team
date: 2017-02-19
modified: 2025-10-17
tags:
  - attack.persistence
  - attack.privilege-escalation
  - attack.initial-access
  - attack.stealth
  - attack.t1078
logsource:
  product: windows
  service: security
detection:
  selection_eid:
    EventID:
      - 4625
      - 4776
  selection_status:
    - Status:
        - "0xC0000072"
        - "0xC000006F"
        - "0xC0000070"
        - "0xC0000413"
        - "0xC000018C"
        - "0xC000015B"
    - SubStatus:
        - "0xC0000072"
        - "0xC000006F"
        - "0xC0000070"
        - "0xC0000413"
        - "0xC000018C"
        - "0xC000015B"
  filter:
    SubjectUserSid: S-1-0-0
  condition: all of selection_* and not filter
falsepositives:
  - User using a disabled account
level: medium
license: DRL-1.1
related:
  - id: 9eb99343-d336-4020-a3cd-67f3819e68ee
    type: derived

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