[role="xpack"] [[audit-log-output]] === Logfile audit output The `logfile` audit output is the default output for auditing. It writes data to the `_access.log` file in the logs directory. [float] [[audit-log-entry-format]] === Log entry format The format of a log entry is: [source,txt] ---------------------------------------------------------------------------- [] [] [] [] ---------------------------------------------------------------------------- `` :: When the event occurred. You can configure the timestamp format in `log4j2.properties`. `` :: Information about the local node that generated the log entry. You can control what node information is included by configuring the {ref}/auditing-settings.html#node-audit-settings[local node info settings]. `` :: The layer from which this event originated: `rest`, `transport` or `ip_filter`. `` :: The type of event that occurred: `anonymous_access_denied`, `authentication_failed`, `access_denied`, `access_granted`, `connection_granted`, `connection_denied`. `` :: A comma-separated list of key-value pairs that contain data pertaining to the event. Formatted as `attr1=[val1], attr2=[val2]`. See <> for the attributes that can be included for each type of event. [float] [[audit-log-settings]] === Logfile output settings The events and some other information about what gets logged can be controlled using settings in the `elasticsearch.yml` file. See {ref}/auditing-settings.html#event-audit-settings[Audited Event Settings] and {ref}/auditing-settings.html#node-audit-settings[Local Node Info Settings]. IMPORTANT: No filtering is performed when auditing, so sensitive data may be audited in plain text when including the request body in audit events. [[logging-file]] You can also configure how the logfile is written in the `log4j2.properties` file located in `ES_PATH_CONF`. By default, audit information is appended to the `_access.log` file located in the standard Elasticsearch `logs` directory (typically located at `$ES_HOME/logs`). The file rolls over on a daily basis. [float] [[audit-log-ignore-policy]] === Logfile audit events ignore policies The comprehensive audit trail is necessary to ensure accountability. It offers tremendous value during incident response and can even be required for demonstrating compliance. The drawback of an audited system is represented by the inevitable performance penalty incurred. In all truth, the audit trail spends _I/O ops_ that are not available anymore for the user's queries. Sometimes the verbosity of the audit trail may become a problem that the event type restrictions, <>, will not alleviate. *Audit events ignore policies* are a finer way to tune the verbosity of the audit trail. These policies define rules that match audit events which will be _ignored_ (read as: not printed). Rules match on the values of attributes of audit events and complement the <> method. Imagine the corpus of audit events and the policies chopping off unwanted events. IMPORTANT: When utilizing audit events ignore policies you are acknowledging potential accountability gaps that could render illegitimate actions undetectable. Please take time to review these policies whenever your system architecture changes. A policy is a named set of filter rules. Each filter rule applies to a single event attribute, one of the `users`, `realms`, `roles` or `indices` attributes. The filter rule defines a list of {ref}/query-dsl-regexp-query.html#regexp-syntax[Lucene regexp], *any* of which has to match the value of the audit event attribute for the rule to match. A policy matches an event if *all* the rules comprising it match the event. An audit event is ignored, therefore not printed, if it matches *any* policy. All other non-matching events are printed as usual. All policies are defined under the `xpack.security.audit.logfile.events.ignore_filters` settings namespace. For example, the following policy named _example1_ matches events from the _kibana_ or _admin_user_ principals **and** operating over indices of the wildcard form _app-logs*_: [source,yaml] ---------------------------- xpack.security.audit.logfile.events.ignore_filters: example1: users: ["kibana", "admin_user"] indices: ["app-logs*"] ---------------------------- An audit event generated by the _kibana_ user and operating over multiple indices , some of which do not match the indices wildcard, will not match. As expected, operations generated by all other users (even operating only on indices that match the _indices_ filter) will not match this policy either. Audit events of different types may have <>. If an event does not contain an attribute for which some policy defines filters, the event will not match the policy. For example, the following policy named _example2_, will never match `authentication_success` or `authentication_failed` events, irrespective of the user's roles, because these event schemas do not contain the `role` attribute: [source,yaml] ---------------------------- xpack.security.audit.logfile.events.ignore_filters: example2: roles: ["admin", "ops_admin_*"] ---------------------------- Likewise, any events of users with multiple roles, some of which do not match the regexps will not match this policy. For completeness, although practical use cases should be sparse, a filter can match a missing attribute of an event, using the empty string ("") or the empty list ([]). For example, the following policy will match events that do not have the `indices` attribute (`anonymous_access_denied`, `authentication_success` and other types) as well as events over the _next_ index. [source,yaml] ---------------------------- xpack.security.audit.logfile.events.ignore_filters: example3: indices: ["next", ""] ----------------------------