IdentityLogonEvents - IsNtlmV1
Hi, I cannot find documentation on how the IdentityLogonEvents table's AdditionalFields.IsNtlmV1 populated. In a demo environment, I intentionally "enforced" NTLMv1 and made an NTLMv1 connection to a domain controller. On the DC's Security log, event ID 4624 shows correct info: Detailed Authentication Information: Logon Process: NtLmSsp Authentication Package: NTLM Transited Services: - Package Name (NTLM only): NTLM V1 Key Length: 128 On MDI side however it looks like this: (using the following KQL to display relevant info here: IdentityLogonEvents | where ReportId == @"f70dbd37-af8e-4e4e-a77d-b4250f9e0d0b" | extend todynamic(AdditionalFields) | project TimeGenerated, ActionType, Application, LogonType, Protocol,IsNtlmV1 = AdditionalFields.IsNtlmV1 ) TimeGenerated ActionType Application LogonType Protocol IsNtlmV1 Nov 28, 2025 10:43:05 PM LogonSuccess Active Directory Credentials validation Ntlm false Can someone please explain, under which circumstances will the IsNtlmV1 property become "true"? Thank you in advanceLesson Learned #503: Lessons Learned Using JDBC Logging with Microsoft JDBC Driver for SQL Server
A few days ago, our customer encountered connectivity issues while using HikariCP in their Java application. To troubleshoot the problem, we enabled detailed logging for the Microsoft JDBC Driver for SQL Server. This logging gave me a lot of information and details, following I would like to share my lessons learned here.
