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type: resourceresource: AuditEvent

AuditEvent

Introduction

Scope and Usage

The audit event is based on the IHE-ATNA Audit record definitions, originally from RFC 3881, and now managed by DICOM (see DICOM Part 15 Annex A5).

This resource is managed collaboratively between HL7, DICOM, and IHE.

A record of an event relevant for purposes such as operations, privacy, security, maintenance, and performance analysis.

Background and Context

All actors - such as applications, processes, and services - involved in an auditable event SHOULD record an AuditEvent. This will likely result in multiple AuditEvent entries that show whether privacy and security safeguards, such as access control, are properly functioning across an enterprise's system-of-systems. Thus, it is typical to get an auditable event recorded by both the application in a workflow process and the servers that support them. For this reason, duplicate entries are expected, which is helpful because it MAY aid in the detection of security, privacy, or other operational problems. For example, fewer than expected actors being recorded in a multi-actor process or attributes related to those records being in conflict, which is an indication of a security problem. There MAY be non-participating actors, such as trusted intermediary, that also detect a security, privacy, or operational relevant event and thus would record an AuditEvent.

Security relevant events are not limited to communications or RESTful events. They include:

See the Audit Event Category vocabulary for guidance on some security relevant event categories.

The AuditEvent resource holds the details of an event in terms of who, what, where, when, and why. Where the identification of the who participated is the agent. An agent can be a person, an organization, software, device, or other actors that MAY be ascribed responsibility. What objects were used/created/updated is recorded as the entity. An entity is an identifiable physical, digital, conceptual or other kind of thing; entities MAY be real or imaginary.

The content of an AuditEvent is primarily intended for administrative use; used by security system administrators, security and privacy information managers, records management personnel, etc. The AuditEvent MAY also inform the Patient about uses of their data. This content can be accessible or used directly by other healthcare users, such as providers or patients for gaining insight into who and what has been done. The AuditEvent record includes very sensitive information so access to the AuditEvent would be highly privileged and controlled. For example, when providing AuditEvent to a patient the data feed would be limited to the Patient compartment, and the content MAY be subsetted or masked in order to meet privacy needs. The AuditEvent record is not intended to replace other audit logs, but rather used to enhance them, or to be used as an API to many audit logs.

Relationship of AuditEvent and Provenance resources are often (though not exclusively) created by the application responding to the create/read/query/update/delete/execute etc. event. A Provenance resource contains overlapping information, but is a record-keeping assertion that gathers information about the context in which the information in a resource "came to be" in its current state, e.g., whether it was created de novo or obtained from another entity in whole, part, or by transformation. Provenance resources are prepared by the application that initiates the create/update of the resource and MAY be persisted with the AuditEvent target resource.

Notes

Using Coded Values

The AuditEvent resource and the ATNA Audit record are used in many contexts throughout healthcare. The coded values defined in the "extensible" bindings above are those widely used and/or defined by DICOM, IHE or ISO, who defined these codes to meet very specific use cases. These codes SHOULD be used when they are suitable. When needed, other codes can be defined.

Note: When using codes from a vocabulary, the display element for the code can be left off to keep the AuditEvent size small and minimize impact of a large audit log of similar entries.

The set of codes defined for this resource is expected to grow over time, and additional codes MAY be proposed / requested using the "Propose a change" link above below.

Event codes for Common Scenarios

This table summarizes common event scenarios, and the codes that SHOULD be used for each case.

ScenariocategorycodeactionOther
User Login (example)110114 User Authentication110122 User AuthenticationE ExecuteOne agent which contains the details of the logged-in user.
User Logout (example)110114 User Authentication110123 User LogoutE ExecuteOne agent which contains the details of the logged-out user.
REST operation logged on server (example)rest RESTful Operation[code] defined for operation* (see below)Agent for logged in user, if available.
Search operation logged on server (example)rest RESTful Operation[code] defined for operationE ExecuteAgent for logged in user, if available, and one object with a query element. The Execute action is used as the server must execute the search parameters to get the results, whereas a Read action identifies a specific object.
Break-Glass started (example)110113 Security Alert110127 Emergency Override StartedE ExecuteAgent is the user who is authorized to break-glass and has declared an emergency override. Note there is an Emergency Override Stopped code that can be used to indicate the closing of the break-glass event, when it is known.

Audit Event Actions for RESTful operations:

OperationAction
createC
read, vread, history-instance, history-type, history-systemR
updateU
deleteD
transaction, operation, conformance, validate, search, search-type, search-systemE

Recording Search Events

A search event is recorded as an Execute action as the server must execute the search parameters to get the results. The category is a rest operation. The code SHOULD be search. The Server is identified in an .agent as the role Destination Role ID, and the client is identified in an .agent as the role Source Role ID. Additional .agent elements MAY be used to identify user, application, organization, etc.

A Search Event records one .entity element that holds the search request, and SHOULD NOT record the contents of the search response so as to limit duplication of sensitive health information that is already present in the system, and discoverable by replaying the search request.

The AuditEvent.entity.query SHALL hold the whole WHOLE http header and body encoded as base64binary. This SHOULD preserve as much of the raw http header and body as possible to best capture any attempts by clients or intermediaries to misbehave. There SHOULD be no sanitization or normalization of this value.

The FHIR specification defines a harmonized search parameter string, which is returned in the searchset bundle as the .link.url on the .link for self. This string could be recorded in the AuditEvent.entry.description as it is well behaved and represents what was actually processed as search parameters. See: conformance

Where there are identifiable Patient subject(s) associated with the returned Resource(s), the AuditEvent.patient SHOULD be used to record the Patient as the subject of the data or activity. When multiple patient results are returned one AuditEvent is created for every Patient identified in the resulting search set. Note this is true when the search set bundle includes any number of resources that collectively reference multiple Patients. This includes one Resource with multiple subject values, or many Resources with single subject values that are different.

Encoding a FHIR operation outcome

FHIR interactions can result in a rich description of the outcome using the OperationOutcome. The OperationOutcome Resource is a collection of error, warning or information messages that result from a system action. This describes in detail the outcome of some operation, such as when a RESTful operation fails.

When recording into an AuditEvent that some FHIR interaction has happened, the AuditEvent SHOULD include the OperationOutcome from that FHIR interaction. This is done by placing the OperationOutcome into an AuditEvent.entity. Likely as a contained resource, given that OperationOutcome resources often are not persisted.

entity.what is the OperationOutcome -- Likely contained

entity.type is code [OperationOutcome](codesystem-fhir-types#fhir-types-OperationOutcome)

entity.description explains why this OperationOutcome was included.

See transaction failure example: When a client attempts to post (create) an Observation Resource, using a server Patient endpoint; this would result in an error with an OperationOutcome.

authorization and agent.authorization

The AuditEvent provides the element AuditEvent.authorization to convey the purpose of use for the whole event and AuditEvent.agent.authorization to convey the purpose of use that a particular actor (machine, person, software) was involved in the event.

AuditEvent.authorization is an element at the level of AuditEvent and can convey the purpose of the activity that resulted in the event. This will occur when the system that is reporting the event is aware of the purpose of the event. A specific example would be a radiology reporting system where a radiologist has created and is sending a finished report. This system likely knows the purpose, e.g., "treatment". It is multi-valued because the one event MAY be related to multiple purposes.

It is also commonplace that the reporting system does not have information about the purpose of the event. In these cases, the event report would not have an authorization.

It is also likely that the same event will be reported from different perspectives, e.g., by both the sender and recipient of a communication. These two different perspectives can have different knowledge regarding the purposeOfUse authorization.

AuditEvent.agent.authorization is an element at the level of agent within AuditEvent. This describes the reason that this person, machine, or software is participating in the activity that resulted in the event. For example, an individual person participating in the event MAY assert a purpose of use from their perspective. It is also possible that they are participating for multiple reasons and report multiple purposeOfUse.

The reporting system might not have knowledge regarding why a particular machine or person was involved and would omit this element in those cases.

When the same event is reported from multiple perspectives, the reports can have different knowledge regarding the purpose.

Patient as subject of data or activity reference in AuditEvent.patient

It is a best practice to include a reference to the Patient affected by any auditable event, in order to enable Privacy Accounting of Disclosures and Access Logs, and to enable privacy office and security office audit log analysis. Reasonable efforts SHOULD be taken to assure the Patient is recorded, but it is recognized that there are times when this is not reasonable.

Where an activity impacts more than one Patient subject; multiple AuditEvent resources SHOULD be recorded, one for each Patient subject. This best enables segmentation of the AuditEvent details so as to limit the Privacy impact. The use of multiple AuditEvent is a best-practice and SHOULD be driven by a Policy. There will be cases where the use of multiple AuditEvent resources are not necessary, such as public health reporting.

To record a REST interaction or $operation, it is often necessary to complete the transaction in order to determine the Patient subject. Inspection of the potential returned results MAY be necessary. Some REST and $operations include parameters limiting the results to a specific Patient, in these cases this parameter informs the inclusion of the Patient reference.

Implementation Guides MAY make the AuditEvent requirements more clear given the workflow or security context mandated by the Implementation Guide.

StructureDefinition

Elements (Simplified)

Mappings

Implementation Guide

implementationguide-AuditEvent-core.xml

<?xml version="1.0" encoding="UTF-8"?>

<ImplementationGuide xmlns="http://hl7.org/fhir">
  <id value="AuditEvent-core"/>
  <identifier>
    <system value="urn:ietf:rfc:3986"/>
    <value value="urn:oid:2.16.840.1.113883.4.642.30.2"/>
  </identifier>
  <version value="0.01"/>
  <name value="AuditEventHL7Extensions"/>
  <title value="Audit Event  H L7  Extensions"/>
  <status value="draft"/>
  <date value="1970-01-01T10:00:00+10:00"/>
  <publisher value="Health Level Seven, Inc. - Security WG"/>
  <description value="Defines common extensions used with or related to the AuditEvent resource"/>
</ImplementationGuide>

Resource Packs

list-AuditEvent-packs.xml

<?xml version="1.0" encoding="UTF-8"?>

<List xmlns="http://hl7.org/fhir">
  <id value="AuditEvent-packs"/>
  <status value="current"/>
  <mode value="working"/>
  <entry>
    <item>
      <reference value="ImplementationGuide/AuditEvent-core"/>
    </item>
  </entry>
</List>

Search Parameters

Full Search Parameters

Examples

Full Examples

Mapping Exceptions

auditevent-event-mapping-exceptions.xml

Divergent Elements

Unmapped Elements

auditevent-fivews-mapping-exceptions.xml

Divergent Elements

Unmapped Elements