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The Advanced Security Information Model (ASIM) Audit Events normalization schema reference (Public preview)

  • Straipsnis

The Microsoft Sentinel Audit events normalization schema represents events associated with the audit trail of information systems. The audit trail logs system configuration activities and policy changes. Such changes are often performed by system administrators, but can also be performed by users when configuring the settings of their own applications.

Every system logs audit events alongside its core activity logs. For example, a Firewall will log events about the network sessions is processes, and audit events about configuration changes applied to the Firewall itself.

For more information about normalization in Microsoft Sentinel, see Normalization and the Advanced Security Information Model (ASIM).

Important

The Audit Event normalization schema is currently in preview. This feature is provided without a service level agreement. We don't recommend it for production workloads.

The Azure Preview Supplemental Terms include additional legal terms that apply to Azure features that are in beta, preview, or otherwise not yet released into general availability.

Schema overview

The main fields of an audit event are:

  • The object, which may be, for example, a managed resource or policy rule, that the event focuses on, represented by the field Object. The field ObjectType specifies the type of the object.
  • The application context of the object, represented by the field TargetAppName, which is aliased by Application.
  • The operation performed on the object, represented by the fields EventType and Operation. While Operation is the value the source reported, EventType is a normalized version that is more consistent across sources.
  • The old and new values for the object, if applicable, represented by OldValue and NewValue respectively.

Audit events also reference the following entities, which are involved in the configuration operation:

  • Actor - The user performing the configuration operation.
  • TargetApp - The application or system for which the configuration operation applies.
  • Target - The system on which TaregtApp* is running.
  • ActingApp - The application used by the Actor to perform the configuration operation.
  • Src - The system used by the Actor to initiate the configuration operation, if different than Target.

The descriptor Dvc is used for the reporting device, which is the local system for sessions reported by an endpoint, and the intermediary or security device in other cases.

Parsers

Deploying and using audit events parsers

Deploy the ASIM audit events parsers from the Microsoft Sentinel GitHub repository. To query across all audit event sources, use the unifying parser imAuditEvent as the table name in your query.

For more information about using ASIM parsers, see the ASIM parsers overview. For the list of the audit event parsers Microsoft Sentinel provides out-of-the-box refer to the ASIM parsers list

Add your own normalized parsers

When implementing custom parsers for the File Event information model, name your KQL functions using the following syntax: imAuditEvent<vendor><Product>. Refer to the article Managing ASIM parsers to learn how to add your custom parsers to the audit event unifying parser.

Filtering parser parameters

The audit events parsers support filtering parameters. While these parameters are optional, they can improve your query performance.

The following filtering parameters are available:

Name Type Description
starttime datetime Filter only events that ran at or after this time. This parameter uses the TimeGenerated field as the time designator of the event.
endtime datetime Filter only events queries that finished running at or before this time. This parameter uses the TimeGenerated field as the time designator of the event.
srcipaddr_has_any_prefix dynamic Filter only events from this source IP address, as represented in the SrcIpAddr field.
eventtype_in string Filter only events in which the event type, as represented in the EventType field is any of the terms provided.
eventresult string Filter only events in which the event result, as represented in the EventResult field is equal to the parameter value.
actorusername_has_any dynamic/string Filter only events in which the ActorUsername includes any of the terms provided.
operation_has_any dynamic/string Filter only events in which Operation field includes any of the terms provided.
object_has_any dynamic/string Filter only events in which Object field includes any of the terms provided.
newvalue_has_any dynamic/string Filter only events in which NewValue field includes any of the terms provided.

Some parameter can accept both list of values of type dynamic or a single string value. To pass a literal list to parameters that expect a dynamic value, explicitly use a dynamic literal. For example: dynamic(['192.168.','10.'])

For example, to filter only audit events with the terms install or update in their Operation field, from the last day , use:

imAuditEvent (operation_has_any=dynamic(['install','update']), starttime = ago(1d), endtime=now())

Schema details

Common ASIM fields

Important

Fields common to all schemas are described in detail in the ASIM Common Fields article.

Common fields with specific guidelines

The following list mentions fields that have specific guidelines for Audit Events:

Field Class Type Description
EventType Mandatory Enumerated Describes the operation audited by the event using a normalized value. Use EventSubType to provide further details, which the normalized value does not convey, and Operation. to store the operation as reported by the reporting device.

For Audit Event records, the allowed values are:
- Set
- Read
- Create
- Delete
- Execute
- Install
- Clear
- Enable
- Disable
- Other

Audit events represent a large variety of operations, and the Other value enables mapping operations that have no corresponding EventType. However, the use of Other limits the usability of the event and should be avoided if possible.
EventSubType Optional String Provides further details, which the normalized value in EventType does not convey.
EventSchema Mandatory String The name of the schema documented here is AuditEvent.
EventSchemaVersion Mandatory String The version of the schema. The version of the schema documented here is 0.1.

All common fields

Fields that appear in the table are common to all ASIM schemas. Any of guidelines specified in this document overrides the general guidelines for the field. For example, a field might be optional in general, but mandatory for a specific schema. For more information on each field, see the ASIM Common Fields article.

Class Fields
Mandatory - EventCount
- EventStartTime
- EventEndTime
- EventType
- EventResult
- EventProduct
- EventVendor
- EventSchema
- EventSchemaVersion
- Dvc
Recommended - EventResultDetails
- EventSeverity
- EventUid
- DvcIpAddr
- DvcHostname
- DvcDomain
- DvcDomainType
- DvcFQDN
- DvcId
- DvcIdType
- DvcAction
Optional - EventMessage
- EventSubType
- EventOriginalUid
- EventOriginalType
- EventOriginalSubType
- EventOriginalResultDetails
- EventOriginalSeverity
- EventProductVersion
- EventReportUrl
- EventOwner
- DvcZone
- DvcMacAddr
- DvcOs
- DvcOsVersion
- DvcOriginalAction
- DvcInterface
- AdditionalFields
- DvcDescription
- DvcScopeId
- DvcScope

Audit fields

Field Class Type Description
Operation Mandatory String The operation audited as reported by the reporting device.
Object Mandatory String The name of the object on which the operation identified by EventType is performed.
ObjectType Mandatory Enumerated The type of Object. Allowed values are:
- Cloud Resource
- Configuration Atom
- Policy Rule
- Other
OldValue Optional String The old value of Object prior to the operation, if applicable.
NewValue Optional String The new value of Object after the operation was performed, if applicable.
Value Alias Alias to NewValue
ValueType Conditional Enumerated The type of the old and new values. Allowed values are
- Other

Actor fields

Field Class Type Description
ActorUserId Optional String A machine-readable, alphanumeric, unique representation of the Actor. For more information, and for alternative fields for other IDs, see The User entity.

Example: S-1-12-1-4141952679-1282074057-627758481-2916039507
ActorScope Optional String The scope, such as Microsoft Entra Domain Name, in which ActorUserId and ActorUsername are defined. or more information and list of allowed values, see UserScope in the Schema Overview article.
ActorScopeId Optional String The scope ID, such as Microsoft Entra Directory ID, in which ActorUserId and ActorUsername are defined. for more information and list of allowed values, see UserScopeId in the Schema Overview article.
ActorUserIdType Conditional UserIdType The type of the ID stored in the ActorUserId field. For more information and list of allowed values, see UserIdType in the Schema Overview article.
ActorUsername Recommended Username The Actor’s username, including domain information when available. For more information, see The User entity.

Example: AlbertE
User Alias Alias to ActorUsername
ActorUsernameType Conditional UsernameType Specifies the type of the user name stored in the ActorUsername field. For more information, and list of allowed values, see UsernameType in the Schema Overview article.

Example: Windows
ActorUserType Optional UserType The type of the Actor. For more information, and list of allowed values, see UserType in the Schema Overview article.

For example: Guest
ActorOriginalUserType Optional UserType The user type as reported by the reporting device.
ActorSessionId Optional String The unique ID of the sign-in session of the Actor.

Example: 102pTUgC3p8RIqHvzxLCHnFlg

Target application fields

Field Class Type Description
TargetAppId Optional String The ID of the application to which the event applies, including a process, browser, or service.

Example: 89162
TargetAppName Optional String The name of the application to which event applies, including a service, a URL, or a SaaS application.

Example: Exchange 365
Application Alias Alias to TargetAppName
TargetAppType Optional AppType The type of the application authorizing on behalf of the Actor. For more information, and allowed list of values, see AppType in the Schema Overview article.
TargetUrl Optional URL The URL associated with the target application.

Example: https://console.aws.amazon.com/console/home?fromtb=true&hashArgs=%23&isauthcode=true&nc2=h_ct&src=header-signin&state=hashArgsFromTB_us-east-1_7596bc16c83d260b

Target system fields

Field Class Type Description
Dst Alias String A unique identifier of the authentication target.

This field may alias the TargerDvcId, TargetHostname, TargetIpAddr, TargetAppId, or TargetAppName fields.

Example: 192.168.12.1
TargetHostname Recommended Hostname The target device hostname, excluding domain information.

Example: DESKTOP-1282V4D
TargetDomain Recommended String The domain of the target device.

Example: Contoso
TargetDomainType Conditional Enumerated The type of TargetDomain. For a list of allowed values and further information, refer to DomainType in the Schema Overview article.

Required if TargetDomain is used.
TargetFQDN Optional String The target device hostname, including domain information when available.

Example: Contoso\DESKTOP-1282V4D

Note: This field supports both traditional FQDN format and Windows domain\hostname format. The TargetDomainType reflects the format used.
TargetDescription Optional String A descriptive text associated with the device. For example: Primary Domain Controller.
TargetDvcId Optional String The ID of the target device. If multiple IDs are available, use the most important one, and store the others in the fields TargetDvc<DvcIdType>.

Example: ac7e9755-8eae-4ffc-8a02-50ed7a2216c3
TargetDvcScopeId Optional String The cloud platform scope ID the device belongs to. TargetDvcScopeId map to a subscription ID on Azure and to an account ID on AWS.
TargetDvcScope Optional String The cloud platform scope the device belongs to. TargetDvcScope map to a subscription ID on Azure and to an account ID on AWS.
TargetDvcIdType Conditional Enumerated The type of TargetDvcId. For a list of allowed values and further information, refer to DvcIdType in the Schema Overview article.

Required if TargetDeviceId is used.
TargetDeviceType Optional Enumerated The type of the target device. For a list of allowed values and further information, refer to DeviceType in the Schema Overview article.
TargetIpAddr Optional IP Address The IP address of the target device.

Example: 2.2.2.2
TargetDvcOs Optional String The OS of the target device.

Example: Windows 10
TargetPortNumber Optional Integer The port of the target device.

Acting Application fields

Field Class Type Description
ActingAppId Optional String The ID of the application that initiated the activity reported, including a process, browser, or service.

For example: 0x12ae8
ActiveAppName Optional String The name of the application that initiated the activity reported, including a service, a URL, or a SaaS application.

For example: C:\Windows\System32\svchost.exe
ActingAppType Optional AppType The type of acting application. For more information, and allowed list of values, see AppType in the Schema Overview article.
HttpUserAgent Optional String When authentication is performed over HTTP or HTTPS, this field's value is the user_agent HTTP header provided by the acting application when performing the authentication.

For example: Mozilla/5.0 (iPhone; CPU iPhone OS 12_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/12.0 Mobile/15E148 Safari/604.1

Source system fields

Field Class Type Description
Src Alias String A unique identifier of the source device.

This field might alias the SrcDvcId, SrcHostname, or SrcIpAddr fields.

Example: 192.168.12.1
SrcIpAddr Recommended IP address The IP address from which the connection or session originated.

Example: 77.138.103.108
IpAddr Alias Alias to SrcIpAddr, or to TargetIpAddr if SrcIpAddr is not provided.
SrcPortNumber Optional Integer The IP port from which the connection originated. Might not be relevant for a session comprising multiple connections.

Example: 2335
SrcHostname Recommended Hostname The source device hostname, excluding domain information. If no device name is available, store the relevant IP address in this field.

Example: DESKTOP-1282V4D
SrcDomain Recommended String The domain of the source device.

Example: Contoso
SrcDomainType Conditional DomainType The type of SrcDomain. For a list of allowed values and further information, refer to DomainType in the Schema Overview article.

Required if SrcDomain is used.
SrcFQDN Optional String The source device hostname, including domain information when available.

Note: This field supports both traditional FQDN format and Windows domain\hostname format. The SrcDomainType field reflects the format used.

Example: Contoso\DESKTOP-1282V4D
SrcDescription Optional String A descriptive text associated with the device. For example: Primary Domain Controller.
SrcDvcId Optional String The ID of the source device. If multiple IDs are available, use the most important one, and store the others in the fields SrcDvc<DvcIdType>.

Example: ac7e9755-8eae-4ffc-8a02-50ed7a2216c3
SrcDvcScopeId Optional String The cloud platform scope ID the device belongs to. SrcDvcScopeId map to a subscription ID on Azure and to an account ID on AWS.
SrcDvcScope Optional String The cloud platform scope the device belongs to. SrcDvcScope map to a subscription ID on Azure and to an account ID on AWS.
SrcDvcIdType Conditional DvcIdType The type of SrcDvcId. For a list of allowed values and further information, refer to DvcIdType in the Schema Overview article.

Note: This field is required if SrcDvcId is used.
SrcDeviceType Optional DeviceType The type of the source device. For a list of allowed values and further information, refer to DeviceType in the Schema Overview article.
SrcSubscriptionId Optional String The cloud platform subscription ID the source device belongs to. SrcSubscriptionId map to a subscription ID on Azure and to an account ID on AWS.
SrcGeoCountry Optional Country The country associated with the source IP address.

Example: USA
SrcGeoRegion Optional Region The region within a country associated with the source IP address.

Example: Vermont
SrcGeoCity Optional City The city associated with the source IP address.

Example: Burlington
SrcGeoLatitude Optional Latitude The latitude of the geographical coordinate associated with the source IP address.

Example: 44.475833
SrcGeoLongitude Optional Longitude The longitude of the geographical coordinate associated with the source IP address.

Example: 73.211944

Inspection fields

The following fields are used to represent that inspection performed by a security system.

Field Class Type Description
RuleName Optional String The name or ID of the rule by associated with the inspection results.
RuleNumber Optional Integer The number of the rule associated with the inspection results.
Rule Alias String Either the value of RuleName or the value of RuleNumber. If the value of RuleNumber is used, the type should be converted to string.
ThreatId Optional String The ID of the threat or malware identified in the audit activity.
ThreatName Optional String The name of the threat or malware identified in the audit activity.
ThreatCategory Optional String The category of the threat or malware identified in audit file activity.
ThreatRiskLevel Optional Integer The risk level associated with the identified threat. The level should be a number between 0 and 100.

Note: The value might be provided in the source record by using a different scale, which should be normalized to this scale. The original value should be stored in ThreatRiskLevelOriginal.
ThreatOriginalRiskLevel Optional String The risk level as reported by the reporting device.
ThreatConfidence Optional Integer The confidence level of the threat identified, normalized to a value between 0 and a 100.
ThreatOriginalConfidence Optional String The original confidence level of the threat identified, as reported by the reporting device.
ThreatIsActive Optional Boolean True if the threat identified is considered an active threat.
ThreatFirstReportedTime Optional datetime The first time the IP address or domain were identified as a threat.
ThreatLastReportedTime Optional datetime The last time the IP address or domain were identified as a threat.
ThreatIpAddr Optional IP Address An IP address for which a threat was identified. The field ThreatField contains the name of the field ThreatIpAddr represents.
ThreatField Optional Enumerated The field for which a threat was identified. The value is either SrcIpAddr or TargetIpAddr.

Next steps

For more information, see: