4777 Security log · Kerberos Authentication Service low severity low volume

Windows Event ID 4777 — The domain controller failed to validate the credentials for an account

DC failed to validate account credentials. Rarely generated — indicates specific validation failures.

Why event 4777 matters

Credential validation infrastructure issues. Monitor for clusters related to specific service accounts.

How to detect it

Correlate with 4776 and 4771 for comprehensive authentication failure picture.

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

Detection queries

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

Sentinel / Defender KQL
SecurityEvent
| where EventID == 4777   // The domain controller failed to validate the credentials for an account
| project TimeGenerated, Computer, SubjectUserName, TargetUserName, LogonType, IpAddress, WorkstationName
| sort by TimeGenerated desc
Splunk SPL
index=* sourcetype="WinEventLog:Security" EventCode=4777
| stats count earliest(_time) as first_seen latest(_time) as last_seen by ComputerName
| sort - count   `# The domain controller failed to validate the credentials for an account — add EventData fields: SubjectUserName, TargetUserName, LogonType, IpAddress`
Hunt event 4777 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 4771 Kerberos pre-authentication failed 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) 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 4777?

The domain controller failed to validate the credentials for an account. DC failed to validate account credentials. Rarely generated — indicates specific validation failures.

Which log records event 4777?

Event 4777 is written to the Security channel by Microsoft-Windows-Security-Auditing. Advanced Audit Policy — enable the 'Kerberos Authentication Service' subcategory (Success and/or Failure).

How do you detect activity around event 4777?

Correlate with 4776 and 4771 for comprehensive authentication failure picture.