The Advanced Security Information Model (ASIM) File Event normalization schema reference (Public preview)

The File Event normalization schema is used to describe file activity such as creating, modifying, or deleting files or documents. Such events are reported by operating systems, file storage systems such as Azure Files, and document management systems such as Microsoft SharePoint.

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

Important

The File Event normalization schema is currently in PREVIEW. This feature is provided without a service level agreement, and is not recommended 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.

Parsers

Deploying and using file activity parsers

Deploy the ASIM File Activity parsers from the Microsoft Sentinel GitHub repository. To query across all File Activity sources, use the unifying parser imFileEvent as the table name in your query.

For more information about using ASIM parsers, see the ASIM parsers overview. For the list of the file activity 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: imFileEvent<vendor><Product.

Refer to the article Managing ASIM parsers to learn how to add your custom parsers to the file activity unifying parser.

Normalized content

For a full list of analytics rules that use normalized File Activity events, see File Activity security content.

Schema overview

The File Event information model is aligned to the OSSEM Process entity schema.

The File Event schema references the following entities, which are central to file activities:

  • Actor. The user that initiated the file activity
  • ActingProcess. The process used by the Actor to initiate the file activity
  • TargetFile. The file on which the operation was performed
  • Source File (SrcFile). Stores file information prior to the operation.

The relationship between these entities is best demonstrated as follows: An Actor performs a file operation using an Acting Process, which modifies the Source File to Target File.

For example: JohnDoe (Actor) uses Windows File Explorer (Acting process) to rename new.doc (Source File) to old.doc (Target File).

Schema details

Common fields

Important

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

Fields with specific guidelines for the File Event schema

The following list mentions fields that have specific guidelines for File activity events:

Field Class Type Description
EventType Mandatory Enumerated Describes the operation reported by the record.

Supported values include:

- FileAccessed
- FileCreated
- FileModified
- FileDeleted
- FileRenamed
- FileCopied
- FileMoved
- FolderCreated
- FolderDeleted
- FolderMoved
- FolderModified
- FileCreatedOrModified
EventSubType Optional Enumerated Describes details about the operation reported in EventType. Supported values per event type include:
- FileCreated - Upload, Checkin
- FileModified - Checkin
- FileCreatedOrModified - Checkin
- FileAccessed - Download, Preview, Checkout, Extended
- FileDeleted - Recycled, Versions, Site
EventSchema Mandatory String The name of the schema documented here is FileEvent.
EventSchemaVersion Mandatory String The version of the schema. The version of the schema documented here is 0.2.1
Dvc fields - - For File activity events, device fields refer to the system on which the file activity occurred.

Important

The EventSchema field is currently optional but will become Mandatory on September 1st 2022.

All common fields

Fields that appear in the table are common to all ASIM schemas. Any of the schema specific guidelines 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 to 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

Target file fields

The following fields represent information about the target file in a file operation. If the operation involves a single file, FileCreate for example, it is represented by the target file fields.

Field Class Type Description
TargetFileCreationTime Optional Date/Time The time at which the target file was created.
TargetFileDirectory Optional String The target file folder or location. This field should be similar to the TargetFilePath field, without the final element.

Note: A parser can provide this value if the value available in the log source and does not need to be extracted from the full path.
TargetFileExtension Optional String The target file extension.

Note: A parser can provide this value if the value available in the log source and does not need to be extracted from the full path.
TargetFileMimeType Optional Enumerated The Mime, or Media, type of the target file. Allowed values are listed in the IANA Media Types repository.
TargetFileName Recommended String The name of the target file, without a path or a location, but with an extension if relevant. This field should be similar to the final element in the TargetFilePath field.
FileName Alias Alias to the TargetFileName field.
TargetFilePath Mandatory String The full, normalized path of the target file, including the folder or location, the file name, and the extension. For more information, see Path structure.

Note: If the record does not include folder or location information, store the filename only here.

Example: C:\Windows\System32\notepad.exe
TargetFilePathType Mandatory Enumerated The type of TargetFilePath. For more information, see Path structure.
FilePath Alias Alias to the TargetFilePath field.
TargetFileMD5 Optional MD5 The MD5 hash of the target file.

Example: 75a599802f1fa166cdadb360960b1dd0
TargetFileSHA1 Optional SHA1 The SHA-1 hash of the target file.

Example:
d55c5a4df19b46db8c54
c801c4665d3338acdab0
TargetFileSHA256 Optional SHA256 The SHA-256 hash of the target file.

Example:
e81bb824c4a09a811af17deae22f22dd
2e1ec8cbb00b22629d2899f7c68da274
TargetFileSHA512 Optional SHA512 The SHA-512 hash of the source file.
Hash Alias Alias to the best available Target File hash.
HashType Recommended String The type of hash stored in the HASH alias field, allowed values are MD5, SHA, SHA256, SHA512 and IMPHASH. Mandatory if Hash is populated.
TargetFileSize Optional Long The size of the target file in bytes.

Source file fields

The following fields represent information about the source file in a file operation that has both a source and a destination, such as copy. If the operation involves a single file, it is represented by the target file fields.

Field Class Type Description
SrcFileCreationTime Optional Date/Time The time at which the source file was created.
SrcFileDirectory Optional String The source file folder or location. This field should be similar to the SrcFilePath field, without the final element.

Note: A parser can provide this value if the value is available in the log source, and does not need to be extracted from the full path.
SrcFileExtension Optional String The source file extension.

Note: A parser can provide this value the value is available in the log source, and does not need to be extracted from the full path.
SrcFileMimeType Optional Enumerated The Mime or Media type of the source file. Supported values are listed in the IANA Media Types repository.
SrcFileName Recommended String The name of the source file, without a path or a location, but with an extension if relevant. This field should be similar to the last element in the SrcFilePath field.
SrcFilePath Recommended String The full, normalized path of the source file, including the folder or location, the file name, and the extension.

For more information, see Path structure.

Example: /etc/init.d/networking
SrcFilePathType Recommended Enumerated The type of SrcFilePath. For more information, see Path structure.
SrcFileMD5 Optional MD5 The MD5 hash of the source file.

Example: 75a599802f1fa166cdadb360960b1dd0
SrcFileSHA1 Optional SHA1 The SHA-1 hash of the source file.

Example:
d55c5a4df19b46db8c54
c801c4665d3338acdab0
SrcFileSHA256 Optional SHA256 The SHA-256 hash of the source file.

Example:
e81bb824c4a09a811af17deae22f22dd
2e1ec8cbb00b22629d2899f7c68da274
SrcFileSHA512 Optional SHA512 The SHA-512 hash of the source file.
SrcFileSize Optional Long The size of the source file in bytes.

Actor fields

Field Class Type Description
ActorUserId Recommended String A machine-readable, alphanumeric, unique representation of the Actor. For the supported format for different ID types, refer to the User entity.

Example: S-1-12
ActorScope Optional String The scope, such as Azure AD tenant, 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 Azure AD Directory ID, in which ActorUserId and ActorUsername are defined. or more information and list of allowed values, see UserScopeId in the Schema Overview article.
ActorUserIdType Conditional String The type of the ID stored in the ActorUserId field. For a list of allowed values and further information, refer to UserIdType in the Schema Overview article.
ActorUsername Mandatory String The Actor username, including domain information when available. For the supported format for different ID types, refer to the User entity. Use the simple form only if domain information isn't available.

Store the Username type in the ActorUsernameType field. If other username formats are available, store them in the fields ActorUsername<UsernameType>.

Example: AlbertE
User Alias Alias to the ActorUsername field.

Example: CONTOSO\dadmin
ActorUsernameType Conditional Enumerated Specifies the type of the user name stored in the ActorUsername field. For a list of allowed values and further information, refer to UsernameType in the Schema Overview article.

Example: Windows
ActorSessionId Optional String The unique ID of the login session of the Actor.

Example: 999

Note: The type is defined as string to support varying systems, but on Windows this value must be numeric.

If you are using a Windows machine and used a different type, make sure to convert the values. For example, if you used a hexadecimal value, convert it to a decimal value.
ActorUserType Optional UserType The type of Actor. For a list of allowed values and further information, refer to UserType in the Schema Overview article.

Note: The value might be provided in the source record by using different terms, which should be normalized to these values. Store the original value in the ActorOriginalUserType field.
ActorOriginalUserType Optional String The original destination user type, if provided by the reporting device.

Acting process fields

Field Class Type Description
ActingProcessCommandLine Optional String The command line used to run the acting process.

Example: "choco.exe" -v
ActingProcessName Optional string The name of the acting process. This name is commonly derived from the image or executable file that's used to define the initial code and data that's mapped into the process' virtual address space.

Example: C:\Windows\explorer.exe
Process Alias Alias to ActingProcessName
ActingProcessId Optional String The process ID (PID) of the acting process.

Example: 48610176

Note: The type is defined as string to support varying systems, but on Windows and Linux this value must be numeric.

If you are using a Windows or Linux machine and used a different type, make sure to convert the values. For example, if you used a hexadecimal value, convert it to a decimal value.
ActingProcessGuid Optional string A generated unique identifier (GUID) of the acting process. Enables identifying the process across systems.

Example: EF3BD0BD-2B74-60C5-AF5C-010000001E00

The following fields represent information about the system initiating the file activity, typically when carried over the network.

Field Class Type Description
SrcIpAddr Recommended IP Address When the operation is initiated by a remote system, the IP address of this system.

Example: 185.175.35.214
IpAddr Alias Alias to SrcIpAddr
Src Alias Alias to SrcIpAddr
SrcPortNumber Optional Integer When the operation is initiated by a remote system, the port number from which the connection was initiated.

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

The following fields represent information about the network session when the file activity was carried over the network.

Field Class Type Description
HttpUserAgent Optional String When the operation is initiated by a remote system using HTTP or HTTPS, the user agent used.

For example:
Mozilla/5.0 (Windows NT 10.0; Win64; x64)
AppleWebKit/537.36 (KHTML, like Gecko)
Chrome/42.0.2311.135
Safari/537.36 Edge/12.246
NetworkApplicationProtocol Optional String When the operation is initiated by a remote system, this value is the application layer protocol used in the OSI model.

While this field is not enumerated, and any value is accepted, preferable values include: HTTP, HTTPS, SMB,FTP, and SSH

Example: SMB

Target application fields

The following fields represent information about the destination application performing the file activity on behalf of the user. A destination application is usually related to over-the-network file activity, for example using Saas (Software as a service) applications.

Field Class Type Description
TargetAppName Optional String The name of the destination application.

Example: Facebook
Application Alias Alias to TargetAppName.
TargetAppId Optional String The ID of the destination application, as reported by the reporting device.
TargetAppType Optional AppType The type of the destination application. For a list of allowed values and further information, refer to AppType in the Schema Overview article.

This field is mandatory if TargetAppName or TargetAppId are used.
TargetUrl Optional String When the operation is initiated using HTTP or HTTPS, the URL used.

Example: https://onedrive.live.com/?authkey=...
Url Alias Alias to TargetUrl

Inspection fields

The following fields are used to represent that inspection performed by a security system such an anti-virus system. The thread identified is usually associated with the file on which the activity was performed rather than the activity itself.

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 Conditional String Either the value of kRuleName 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 file activity.
ThreatName Optional String The name of the threat or malware identified in the file activity.

Example: EICAR Test File
ThreatCategory Optional String The category of the threat or malware identified in the file activity.

Example: Trojan
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.
ThreatFilePath Optional String A file path for which a threat was identified. The field ThreatField contains the name of the field ThreatFilePath represents.
ThreatField Optional Enumerated The field for which a threat was identified. The value is either SrcFilePath or DstFilePath.
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.

Path structure

The path should be normalized to match one of the following formats. The format the value is normalized to will be reflected in the respective FilePathType field.

Type Example Notes
Windows Local C:\Windows\System32\notepad.exe Since Windows path names are case insensitive, this type implies that the value is case insensitive.
Windows Share \\Documents\My Shapes\Favorites.vssx Since Windows path names are case insensitive, this type implies that the value is case insensitive.
Unix /etc/init.d/networking Since Unix path names are case-sensitive, this type implies that the value is case-sensitive.

- Use this type for AWS S3. Concatenate the bucket and key names to create the path.

- Use this type for Azure Blob storage object keys.
URL https://1drv.ms/p/s!Av04S_*********we Use when the file path is available as a URL. URLs are not limited to http or https, and any value, including an FTP value, is valid.

Schema updates

These are the changes in version 0.1.1 of the schema:

  • Added the field EventSchema.

There are the changes in version 0.2 of the schema:

  • Added inspection fields.
  • Added the fields ActorScope, TargetUserScope, HashType, TargetAppName, TargetAppId, TargetAppType, SrcGeoCountry, SrcGeoRegion, SrcGeoLongitude, SrcGeoLatitude, ActorSessionId, DvcScopeId, and DvcScope..
  • Added the aliases Url, IpAddr, 'FileName', and Src.

There are the changes in version 0.2.1 of the schema:

  • Added Application as an alias to TargetAppName.
  • Added the field ActorScopeId
  • Added source device related fields.

Next steps

For more information, see: