Microsoft Sentinel Network Session normalization schema reference (Public preview)

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12/07/2021
18 นาทีในการอ่าน

The Network Session normalization schema is used to describe an IP network activity. This includes network connections and network sessions. Such events are reported, for example, by operating systems, routers, firewalls, intrusion prevention systems and web security gateways.

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

Important

This article describes version 0.2.x of the network normalization schema, where version 0.1 was released before ASIM was available and does not align with ASIM in several places. For more information, see Differences between network normalization schema versions.

Important

The Network 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.

Schema overview

The network normalization schema can represent any type of an IP network session, but is specifically designed to provide support for common source types, such as Netflow, Firewalls, and Intrusion prevention systems.

Parsers

Source-agnostic parsers

To use the source-agnostic parsers that unify all of the out-of-the-box parsers, and ensure that your analysis runs across all the configured sources, use the following KQL functions as the table name in your query:

Name	Description	Usage instructions
imNetworkSession	Aggregative parser that uses union to include normalized events from all network session sources.	- Update this parser if you want to add or remove sources from source-agnostic analytics. - Use this function in your source-agnostic queries.
ASimNetworkSession	Similar to the imNetworkSession function, but without parameter support, and therefore does not force the Logs page time picker to use the `custom` value.	- Update these parsers if you want to add or remove sources from source-agnostic analytics. - Use this function in your source-agnostic queries if you don't plan to use parameters.
vimNetworkSession<vendor><product>	Source-specific parsers implement normalization for a specific source. Example: `vimNetworkSessionSysmonLinux`	- Add a source-specific parser for a source when there is no out-of-the-box normalizing parser. Update the `im` aggregative parser to include reference to your new parser. - Update a source-specific parser to resolve parsing and normalization issues. - Use a source-specific parser for source-specific analytics.
ASimNetworkSession<vendor><product>>	Source-specific parsers implement normalization for a specific source. Unlike the `vim` functions, the `ASim` functions do not support parameters.	- Add a source-specific parser for a source when there is no out-of-the-box normalizing parser. Update the aggregative `ASim` parser to include reference to your new parser. - Update a source-specific parser to resolve parsing and normalization issues. - Use an `ASim` source-specific parser for interactive queries when not using parameters.

Deploy ASIM parsers from the Microsoft Sentinel GitHub repository.

Out-of-the-box, source-specific parsers

Microsoft Sentinel provides the following built-in, product-specific Network Session parsers:

Name	Description
Microsoft 365 Defender for Endpoint	- Parametrized: vimNetworkSessionMicrosoft365Defender - Regular: ASimNetworkSessionMicrosoft365Defender
Microsoft Defender for IoT - Endpoint (MD4IoT)	- Parametrized: vimNetworkSessionMD4IoT - Regular: ASimNetworkSessionMD4IoT
Microsoft Sysmon for Linux	- Parametrized: vimNetworkSessionSysmonLinux - Regular: ASimNetworkSessionSysmonLinux
Windows Events Firewall	Windows firewall activity as collected using Windows Events 515x, collected using either the Log Analytics Agent or the Azure Monitor Agent into either the Event or the WindowsEvent table. - Parametrized: vimNetworkSessionMicrosoftWindowsEventFirewall - Regular: ASimNetworkSessionMicrosoftWindowsEventFirewall

Add your own normalized parsers

When implementing custom parsers for the Network Session information model, name your KQL functions using the following syntax:

vimNetworkSession<vendor><Product> for parametrized parsers
ASimNetworkSession<vendor><Product> for regular parsers

Then, add the new parser to imNetworkSession or ASimNetworkSession respectively.

Filtering parser parameters

The im and vim* parsers support filtering parameters. While these parsers are optional, they can improve your query performance.

The following filtering parameters are available:

Name	Type	Description
starttime	datetime	Filter only network sessions that started at or after this time.
endtime	datetime	Filter only network sessions that started running at or before this time.
srcipaddr_has_any_prefix	dynamic	Filter only network sessions for which the source IP address field prefix is in one of the listed values.
dstipaddr_has_any_prefix	dynamic	Filter only network sessions for which the destination IP address field prefix is in one of the listed values.
dstportnum	int	Filter only network sessions with the specified destination port number.
hostname_has_any	dynamic	Filter only the network sessions for which the destination hostname field has any of the values listed.
dvcaction	dynamic	Filter only the network sessions for which the Device Action field is any of the values listed.
eventresult	string	Filter only network sessions with a specific EventResult value.

For example, to filter only Web sessions for a specified list of domain names, use:

let torProxies=dynamic(["tor2web.org", "tor2web.com", "torlink.co",...]);
imNetworkSession (hostname_has_any = torProxies)

Schema details

The Network Sessions information model is aligned is the OSSEM Network entity schema.

To conform with industry best practices, the Network Session schema uses the descriptors Src and Dst to identify the network session source and destination devices, without including the token Dvc in the field name.

So, for example, the source device hostname and IP address are named SrcHostname and SrcIpAddr respectively, and not SrcDvcHostname and SrcDvcIpAddr. The prefix Dvc is only used for the reporting or intermediary device, as applicable.

Fields that describe the user and application associated with the source and destination devices also use the Src and Dst descriptors.

Other ASIM schemas typically use Target instead of Dst.

Common fields

Fields common to all schemas are described in the ASIM schema overview. The following fields have specific guidelines for Process Events:

Field	Class	Type	Description
EventCount	Mandatory	Integer	Netflow sources support aggregation, and the EventCount field should be set to the value of the Netflow FLOWS field. For other sources, the value is typically set to `1`.
EventType	Mandatory	Enumerated	Describes the operation reported by the record. For Network Sessions records, supported values include: - `NetworkConnection` - `NetworkSession`
EventSubType	Optional	String	Additional description of the event type, if applicable. For Network Sessions records, supported values include: - `Start` - `End`
EventSchema	Mandatory	String	The name of the schema documented here is `NetworkSession`.
EventSchemaVersion	Mandatory	String	The version of the schema. The version of the schema documented here is `0.2.1`
DvcAction	Optional	Enumerated	The action taken on the network session. Supported values are: - `Allow` - `Deny` - `Drop` - `Drop ICMP` - `Reset` - `Reset Source` - `Reset Destination` - `Encrypt` - `Decrypt` - `VPNroute` Note: The value may be provided in the source record using different terms, which should be normalized to these values. The original value should be stored in the DvcOriginalAction field. Example: `drop`
Dvc fields			For Network Session Events, device fields refer to the system reporting the Network Session event.

Network session fields

The following fields are common to all network session activity logging:

Field	Class	Type	Description
Dst	Recommended	String	A unique identifier of the server receiving the DNS request. This field may alias the DstDvcId, DstHostname, or DstIpAddr fields. Example: `192.168.12.1`
DstIpAddr	Recommended	IP address	The IP address of the connection or session destination. Example: `2001:db8::ff00:42:8329` Note: This value is mandatory if DstHostname is specified.
DstPortNumber	Optional	Integer	The destination IP port. Example: `443`
DstHostname	Recommended	String	The destination device hostname, excluding domain information. If no device name is available, store the relevant IP address in this field. Example: `DESKTOP-1282V4D` Note: This value is mandatory if DstIpAddr is specified.
Hostname	Alias		Alias to DstHostname
DstDomain	Recommended	String	The domain of the destination device. Example: `Contoso`
DstDomainType	Recommended	Enumerated	The type of DstDomain, if known. Possible values include: - `Windows (contoso\mypc)` - `FQDN (docs.microsoft.com)` Required if DstDomain is used.
DstFQDN	Optional	String	The destination 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 DstDomainType reflects the format used.
DstDvcId	Optional	String	The ID of the destination device as reported in the record. Example: `ac7e9755-8eae-4ffc-8a02-50ed7a2216c3`
DstDvcIdType	Optional	Enumerated	The type of DstDvcId, if known. Possible values include: - `AzureResourceId` - `MDEidIf` If multiple IDs are available, use the first one from the list above, and store the others in the DstDvcAzureResourceId or DstDvcMDEid fields, respectively. Required if DstDeviceId is used.
DstDeviceType	Optional	Enumerated	The type of the destination device. Possible values include: - `Computer` - `Mobile Device` - `IOT Device` - `Other`
DstUserId	Optional	String	A machine-readable, alphanumeric, unique representation of the destination user. Supported formats and types include: - SID (Windows): `S-1-5-21-1377283216-344919071-3415362939-500` - UID (Linux): `4578` - AADID (Azure Active Directory): `9267d02c-5f76-40a9-a9eb-b686f3ca47aa` - OktaId: `00urjk4znu3BcncfY0h7` - AWSId: `72643944673` Store the ID type in the DstUserIdType field. If other IDs are available, we recommend that you normalize the field names to DstUserSid, DstUserUid, DstUserAADID, DstUserOktaId and UserAwsId, respectively. For more information, see The User entity. Example: `S-1-12`
DstUserIdType	Optional	Enumerated	The type of the ID stored in the DstUserId field. Supported values are: `SID`, `UIS`, `AADID`, `OktaId`, and `AWSId`.
DstUsername	Optional	String	The Destination username, including domain information when available. Use one of the following formats and in the following order of priority: - Upn/Email: `johndow@contoso.com` - Windows: `Contoso\johndow` - DN: `CN=Jeff Smith,OU=Sales,DC=Fabrikam,DC=COM` - Simple: `johndow`. Use the Simple form only if domain information is not available. Store the Username type in the DstUsernameType field. If other IDs are available, we recommend that you normalize the field names to DstUserUpn, DstUserWindows and DstUserDn.For more information, see The User entity. Example: `AlbertE`
User	Alias		Alias to DstUsername
DstUsernameType	Optional	Enumerated	Specifies the type of the username stored in the DstUsername field. Supported values include: `UPN`, `Windows`, `DN`, and `Simple`. For more information, see The User entity. Example: `Windows`
DstUserType	Optional	Enumerated	The type of Actor. Supported values include: - `Regular` - `Machine` - `Admin` - `System` - `Application` - `Service Principal` - `Other` Note: The value may be provided in the source record using different terms, which should be normalized to these values. Store the original value in the DstOriginalUserType field.
DstOriginalUserType	Optional	String	The original destination user type, if provided by the source.
DstUserDomain	Optional	String	This field is kept for backward compatibility only. ASIM requires domain information, if available, to be part of the DstUsername field.
DstAppName	Optional	String	The name of the destination application. Example: `Facebook`
DstAppId	Optional	String	The ID of the destination application, as reported by the reporting device. Example: `124`
DstAppType	Optional	String	The type of the application authorizing on behalf of the Actor. Supported values include: - `Process` - `Service` - `Resource` - `URL` - `SaaS application` - `Other` This field is mandatory if DstAppName or DstAppId are used.
DstZone	Optional	String	The network zone of the destination, as defined by the reporting device. Example: `Dmz`
DstInterfaceName	Optional	String	The network interface used for the connection or session by the destination device. Example: `Microsoft Hyper-V Network Adapter`
DstInterfaceGuid	Optional	String	The GUID of the network interface used on the destination device. Example: `46ad544b-eaf0-47ef-` `827c-266030f545a6`
DstMacAddr	Optional	String	The MAC address of the network interface at used for the connection or session by the destination device. Example: `06:10:9f:eb:8f:14`
DstVlanId	Optional	String	The VLAN ID related to the destination device. Examples: `130`
OuterVlanId	Optional	Alias	Alias to DstVlanId. In many cases the VLAN can not be determined as a source or a destination but are characterized as inner or outer. This alias to signifies that DstVlanId should be used when the VLAN is characterized as outer.
DstGeoCountry	Optional	Country	The country associated with the destination IP address. For more information, see Logical types. Example: `USA`
DstGeoRegion	Optional	Region	The region, or state, within a country associated with the destination IP address. For more information, see Logical types. Example: `Vermont`
DstGeoCity	Optional	City	The city associated with the destination IP address. For more information, see Logical types. Example: `Burlington`
DstGeoLatitude	Optional	Latitude	The latitude of the geographical coordinate associated with the destination IP address. For more information, see Logical types. Example: `44.475833`
DstGeoLongitude	Optional	Longitude	The longitude of the geographical coordinate associated with the destination IP address. For more information, see Logical types. Example: `73.211944`
Src	Recommended	String	A unique identifier of the source device. This field may 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. This value is mandatory if SrcHostname is specified. Example: `77.138.103.108`
IpAddr	Alias		Alias to SrcIpAddr
SrcPortNumber	Optional	Integer	The IP port from which the connection originated. May not be relevant for a session comprising multiple connections. Example: `2335`
SrcHostname	Recommended	String	The source device hostname, excluding domain information. If no device name is available, store the relevant IP address in this field.This value is mandatory if SrcIpAddr is specified. Example: `DESKTOP-1282V4D`
SrcDomain	Recommended	String	The domain of the source device. Example: `Contoso`
SrcDomainType	Recommended	Enumerated	The type of SrcDomain, if known. Possible values include: - `Windows` (such as: `contoso`) - `FQDN` (such as: `microsoft.com`) 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`
SrcDvcId	Optional	String	The ID of the source device as reported in the record. For example: `ac7e9755-8eae-4ffc-8a02-50ed7a2216c3`
SrcDvcIdType	Optional	Enumerated	The type of SrcDvcId, if known. Possible values include: - `AzureResourceId` - `MDEid` If multiple IDs are available, use the first one from the list above, and store the others in the SrcDvcAzureResourceId and SrcDvcMDEid, respectively. Note: This field is required if SrcDvcId is used.
SrcDeviceType	Optional	Enumerated	The type of the source device. Possible values include: - `Computer` - `Mobile Device` - `IOT Device` - `Other`
SrcUserId	Optional	String	A machine-readable, alphanumeric, unique representation of the source user. Format and supported types include: - SID (Windows): `S-1-5-21-1377283216-344919071-3415362939-500` - UID (Linux): `4578` - AADID (Azure Active Directory): `9267d02c-5f76-40a9-a9eb-b686f3ca47aa` - OktaId: `00urjk4znu3BcncfY0h7` - AWSId: `72643944673` Store the ID type in the SrcUserIdType field. If other IDs are available, we recommend that you normalize the field names to SrcUserSid, SrcUserUid, SrcUserAadId, SrcUserOktaId and UserAwsId, respectively.For more information, see The User entity. Example: S-1-12
SrcUserIdType	Optional	Enumerated	The type of the ID stored in the SrcUserId field. Supported values include: `SID`, `UIS`, `AADID`, `OktaId`, and `AWSId`.
SrcUsername	Optional	String	The Source username, including domain information when available. Use one of the following formats and in the following order of priority: - Upn/Email: `johndow@contoso.com` - Windows: `Contoso\johndow` - DN: `CN=Jeff Smith,OU=Sales,DC=Fabrikam,DC=COM` - Simple: `johndow`. Use the Simple form only if domain information is not available. Store the Username type in the SrcUsernameType field. If other IDs are available, we recommend that you normalize the field names to SrcUserUpn, SrcUserWindows and SrcUserDn. For more information, see The User entity. Example: `AlbertE`
SrcUsernameType	Optional	Enumerated	Specifies the type of the username stored in the SrcUsername field. Supported values are: `UPN`, `Windows`, `DN`, and `Simple`. For more information, see The User entity. Example: `Windows`
SrcUserType	Optional	Enumerated	The type of Actor. Allowed values are: - `Regular` - `Machine` - `Admin` - `System` - `Application` - `Service Principal` - `Other` Note: The value may be provided in the source record using different terms, which should be normalized to these values. Store the original value in the SrcOriginalUserType field.
SrcOriginalUserType			The original source user type, if provided by the source.
SrcUserDomain	Optional	String	This field is kept for backward compatibility only. ASIM requires domain information, if available, to be part of the SrcUsername field.
SrcAppName	Optional	String	The name of the source application. Example: `filezilla.exe`
SrcAppId	Optional	String	The ID of the destination application, as reported by the reporting device. Example: `124`
SrcAppType	Optional	String	The type of the source application. Supported values include: - `Process` - `Service` - `Resource` - `Other` This field is mandatory if SrcAppName or SrcAppId are used.
SrcZone	Optional	String	The network zone of the source, as defined by the reporting device. Example: `Internet`
SrcIntefaceName	Optional	String	The network interface used for the connection or session by the source device. Example: `eth01`
SrcInterfaceGuid	Optional	String	The GUID of the network interface used on the source device. Example: `46ad544b-eaf0-47ef-` `827c-266030f545a6`
SrcMacAddr	Optional	String	The MAC address of the network interface from which the connection or session originated. Example: `06:10:9f:eb:8f:14`
SrcVlanId	Optional	String	The VLAN ID related to the source device. Examples: `130`
InnerVlanId	Optional	Alias	Alias to SrcVlanId. In many cases the VLAN can not be determined as a source or a destination but are characterized as inner or outer. This alias to signifies that SrcVlanId should be used when the VLAN is characterized as inner.
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`
NetworkApplicationProtocol	Optional	String	The application layer protocol used by the connection or session. If the DstPortNumber value is provided, we recommend that you include NetworkApplicationProtocol too. If the value is not available from the source, derive the value from the DstPortNumber value. Example: `FTP`
NetworkProtocol	Optional	Enumerated	The IP protocol used by the connection or session as listed in IANA protocol assignment. Typically, `TCP`, `UDP` or `ICMP`. Example: `TCP`
NetworkDirection	Optional	Enumerated	The direction of the connection or session, into or out of the organization. Supported values include: `Inbound`, `Outbound`, `Listen`. `Listen` indicates that a device has started accepting network connections, but is not actually, necessarily, connected.
NetworkDuration	Optional	Integer	The amount of time, in milliseconds, for the completion of the network session or connection. Example: `1500`
Duration	Alias		Alias to NetworkDuration
NetworkIcmpCode	Optional	Integer	For an ICMP message, the ICMP message type numeric value as described in RFC 2780 for IPv4 network connections, or in RFC 4443 for IPv6 network connections. If a NetworkIcmpType value is provided, this field is mandatory. If the value is not available from the source, derive the value from the NetworkIcmpType field instead. Example: `34`
NetworkIcmpType	Optional	String	For an ICMP message, the ICMP message type text representation, as described in RFC 2780 for IPv4 network connections, or in RFC 4443 for IPv6 network connections. Example: `Destination Unreachable`
NetworkConnectionHistory	Optional	String	TCP Flags and other potential IP header information.
DstBytes	Recommended	Integer	The number of bytes sent from the destination to the source for the connection or session. If the event is aggregated, DstBytes should be the sum over all aggregated sessions. Example: `32455`
SrcBytes	Recommended	Integer	The number of bytes sent from the source to the destination for the connection or session. If the event is aggregated, SrcBytes should be the sum over all aggregated sessions. Example: `46536`
NetworkBytes	Optional	Integer	Number of bytes sent in both directions. If both BytesReceived and BytesSent exist, BytesTotal should equal their sum. If the event is aggregated, NetworkBytes should be the sum over all aggregated sessions. Example: `78991`
DstPackets	Optional	Integer	The number of packets sent from the destination to the source for the connection or session. The meaning of a packet is defined by the reporting device.If the event is aggregated, DstPackets should be the sum over all aggregated sessions. Example: `446`
SrcPackets	Optional	Integer	The number of packets sent from the source to the destination for the connection or session. The meaning of a packet is defined by the reporting device. If the event is aggregated, SrcPackets should be the sum over all aggregated sessions. Example: `6478`
NetworkPackets	Optional	Integer	The number of packets sent in both directions. If both PacketsReceived and PacketsSent exist, BytesTotal should equal their sum. The meaning of a packet is defined by the reporting device. If the event is aggregated, NetworkPackets should be the sum over all aggregated sessions. Example: `6924`
NetworkSessionId	Optional	string	The session identifier as reported by the reporting device. Example: `172\_12\_53\_32\_4322\_\_123\_64\_207\_1\_80`
SessionId	Alias	String	Alias to NetworkSessionId

Intermediary device fields

The following fields are useful if the record includes information about an intermediary device, such as a Firewall or a Proxy, which relays the network session.

Field	Class	Type	Description
DstNatIpAddr	Optional	IP address	If reported by an intermediary NAT device, the IP address used by the NAT device for communication with the source. Example: `2::1`
DstNatPortNumber	Optional	Integer	If reported by an intermediary NAT device, the port used by the NAT device for communication with the source. Example: `443`
SrcNatIpAddr	Optional	IP address	If reported by an intermediary NAT device, the IP address used by the NAT device for communication with the destination. Example: `4.3.2.1`
SrcNatPortNumber	Optional	Integer	If reported by an intermediary NAT device, the port used by the NAT device for communication with the destination. Example: `345`
DvcInboundInterface	Optional	String	If reported by an intermediary device, the network interface used by the NAT device for the connection to the source device. Example: `eth0`
DvcOutboundInterface	Optional	String	If reported by an intermediary device, the network interface used by the NAT device for the connection to the destination device. Example: `Ethernet adapter Ethernet 4e`

Inspection fields

The following fields are used to represent that inspection which a security device such as a firewall, an IPS or a Web Security Gateway performed:

Field	Class	Type	Description
NetworkRuleName	Optional	String	The name or ID of the rule by which DvcAction was decided upon. Example: `AnyAnyDrop`
NetworkRuleNumber	Optional	Integer	The number of the rule by which DvcAction was decided upon. Example: `23`
Rule	Mandatory	String	Either `NetworkRuleName` or `NetworkRuleNumber`
ThreatId	Optional	String	The ID of the threat or malware identified in the network session. Example: `Tr.124`
ThreatName	Optional	String	The name of the threat or malware identified in the network session. Example: `EICAR Test File`
ThreatCategory	Optional	String	The category of the threat or malware identified in the network session. Example: `Trojan`
ThreatRiskLevel	Optional	Integer	The risk level associated with the Session. The level should be a number between 0 and a 100. Note: The value may be provided in the source record using a different scale, which should be normalized to this scale. The original value should be stored in ThreatRiskLevelOriginal.
ThreatRiskLevelOriginal	Optional	String	The risk level as reported by the reporting device.

Other fields

If the event is reported by one of the endpoints of the network session, it may include information about the process that initiated or terminated the session. In such cases, the ASIM Process Event schema to normalize this information.

Schema updates

These are the changes in version 0.2.1 of the schema:

Added Src and Dst as aliases to a leading identifier for the source and destination systems.
Added the fields NetworkConnectionHistory, SrcVlanId, DstVlanId, InnerVlanId, and OuterVlanId

Next steps

For more information, see: