4771 Security log · Kerberos Authentication Service medium severity medium volume

Windows Event ID 4771 — Kerberos pre-authentication failed

Kerberos TGT request failed. Status codes: 0x18=wrong password, 0x12=account disabled, 0x6=unknown username, 0x17=password expired.

Why event 4771 matters

Kerberos brute force and spray. Generates 4771 instead of 4625 when auth goes directly to DC via Kerberos (e.g., kinit from Linux, kerbrute, nmap Kerberos scripts). Status 0x18 in bulk = spray/brute force.

How to detect it

Alert: >10 Status=0x18 events from single ClientAddress within 5 min. Alert: 0x18 against admin accounts. Correlate with 4740 (lockouts). Must collect from all DCs.

Log source
Security
Advanced Audit Policy — enable the 'Kerberos Authentication Service' subcategory (Success and/or Failure).
Fields to pivot on
TargetUserNameIpAddressTicketEncryptionTypeStatusFailureCode

MITRE ATT&CK mapping

Tactic Technique
Credential Access Brute Force (T1110)

Detection queries

Starting points — adapt the log source, projected fields and thresholds for your environment.

Sigma rule
title: Kerberos Pre-Auth Failure Spike
status: stable
description: Kerberos brute force or password spray
author: theadminstack.com
date: 2026/05/16
logsource:
    product: windows
    service: security
detection:
    selection:
        EventID: 4771
        Status: '0x18'
    condition: selection | count() by ClientAddress > 10
falsepositives:
    - Misconfigured applications
level: medium
tags:
    - attack.credential_access
    - attack.t1110
Sentinel / Defender KQL
SecurityEvent
| where EventID == 4771   // Kerberos pre-authentication failed
| project TimeGenerated, Computer, TargetUserName, IpAddress, TicketEncryptionType, Status, FailureCode
| sort by TimeGenerated desc
Splunk SPL
index=* sourcetype="WinEventLog:Security" EventCode=4771
| stats count earliest(_time) as first_seen latest(_time) as last_seen by ComputerName
| sort - count   `# Kerberos pre-authentication failed — add EventData fields: TargetUserName, IpAddress, TicketEncryptionType, Status`
Hunt event 4771 in Sentinel/Defender →
Build a KQL query for this event in the KQL Query Builder.
Search all event IDs →
Open the interactive Windows Event ID lookup.

Related Kerberos Authentication Service events

4768 A Kerberos authentication ticket (TGT) was requested 4769 A Kerberos service ticket was requested 4770 A Kerberos service ticket was renewed 4772 A Kerberos authentication ticket request failed 4773 A Kerberos service ticket request failed 4774 An account was mapped for logon 4775 An account could not be mapped for logon 4776 The domain controller attempted to validate the credentials for an account (NTLM) 4777 The domain controller failed to validate the credentials for an account 4820 A Kerberos Ticket-Granting-Ticket (TGT) was denied because the device does not meet the access control restrictions 4821 A Kerberos service ticket was denied because the user, device, or both do not meet the access control restrictions 4822 NTLM authentication failed because the account was a member of the Protected Users group

Frequently asked questions

What is Windows Event ID 4771?

Kerberos pre-authentication failed. Kerberos TGT request failed. Status codes: 0x18=wrong password, 0x12=account disabled, 0x6=unknown username, 0x17=password expired.

Which log records event 4771?

Event 4771 is written to the Security channel by Microsoft-Windows-Security-Auditing. Advanced Audit Policy — enable the 'Kerberos Authentication Service' subcategory (Success and/or Failure).

What MITRE ATT&CK techniques map to event 4771?

Event 4771 is associated with: Brute Force (T1110).

How do you detect activity around event 4771?

Alert: >10 Status=0x18 events from single ClientAddress within 5 min. Alert: 0x18 against admin accounts. Correlate with 4740 (lockouts). Must collect from all DCs.