Interpreting JSON Audit Logs

Introduction

With JSON audit logging enabled, details of various events are logged in a regualr way in JSON format. Each event has many attributes, but what do these attributes mean? This page aims to help.

Authentication

Note: Some attributes will still be present when they are inapplicable. For example, if not using NETLOGON (per "serviceDescription"), "netlogonComputer" will be set to "null", "netlogonNegotiateFlags" will be "0x00000000", and other netlogon fields will have similarly empty values.

Regarding the client-, mapped-, and became- account and domain attributes, these follow track the process of the identity claim through various layers. The client has given the client values, which might get converted to different mapped values. If the authentication is successful, the became- attributes pertain to the account we actually ended up with. Do not be surprised if these are often very similar.

Attribute	meaning
authDescription	the authentication type, for example "guest", "bare-NTLM", "plaintext", "simple bind", "interactive", "network", "ServerAuthenticate".
becameAccount	the account name logged in as. This may differ from the account supplied by the client.
becameDomain	the domain logged into.
becameSid	the SID of the authenticated account.
clientAccount	the reported account name from the client.
clientDomain	the reported domain name from the client.
duration	how long the authentication took (up until this field was written).
eventId	a Windows event ID, indicating in broad terms what happened.
localAddress	the server address and port used.
logonId	a random 64 bit identifier to help trace logon events through different stages.
logonType	Windows logon type, for Samba one of 2: Interactive, meaning on this computer 3: Network, over the network 8: NetworkCleartext, using unhash passwords.
mappedAccount	the client account name translated to an AD account name.
mappedDomain	the client domain translated to an AD domain name.
netlogonComputer	the claimed computer name in NETLOGON RPC authentication.
netlogonNegotiateFlags	NETLOGON negotiation option flags, documented in MS-NRPC 3.1.4.2.
netlogonSecureChannelType	indicates the type of NETLOGON channel used. See MS-NRPC 2.2.1.3.13.
netlogonTrustAccount	account used in NETLOGON authentication.
netlogonTrustAccountSid	SID belonging to the NETLOGON trust account.
passwordType	indicates the password algorithm/protocol (e.g. "HMAC-SHA256", "NTLMv2", "arcfour-hmac-md5").
remoteAddress	the claimed address (and port) of the remote client.
serviceDescription	indicates the service type, for example "LDAP", "SMB2", "NETLOGON".
status	an NT STATUS message, usually "NT_STATUS_OK".
version	a version number for the JSON format. It has two parts. major: incremented if fields change meaning minor: incremented if a field is added a change in possible values does not necessarily trigger a version change. This is obviously true for client data, but also applies to e.g. passwordType, where the set of supported password formats can change over time. The version documented here has the value {"major": 1, "minor": 2}.
workstation	the claimed name of the client workstation.

Authorization

nothing yet here.

dsdbChange

nothing here either.