Change Auditor 7.3 - SIEM Integration User Guide


	NOTE: The “Batches sent”, “Last event time in UTC”, “Last event response” and “Events sent” are all indicators that the events are being received by a Syslog server. Any failures receiving the data populate the “Last event response” property in the object with information on why the data was not received.

Table 19. Available parameters


Parameter	Description
-Connection	A connection obtained by using the Connect-CAClient command. See the Change Auditor PowerShell Command Guide for details.
-SubscriptionId (optional)	The ID of an existing Syslog subscription. If specified, the command will only return the Syslog subscription with that ID. If not specified, all Syslog subscriptions are returned.

Example: List defined Syslog subscriptions

Get-CASyslogEventSubscriptions -Connection $connection

Command output

The command returns the following information.

Table 20. Available configuration information
Setting	Description
Id	The subscription ID.
WebhookSubscriptionId	The webhook subscription ID.
Host	The IP address or host name where event data is sent.
Port	The port where event data is sent.
StartTimeUTC	Starting point in time for events being sent.
Subsystems	Subsystems that contain the event data being sent.
Enabled	Whether the subscription is enabled.
HeartbeatUrl	URL for heartbeat notifications.
LastEventTimeUTC	When the last event was sent.
LastEventResponse	Last event response.
LastHeartbeatTimeUTC	When the last heartbeat was sent.
LastHeartbeatResponse	The last heartbeat response. For example, statusCode = OK (200), statusCode = Bad Request (400), or statusCode = Internal Server Error (500).
EventsSent	Number of events sent.
BatchesSent	Number of batches sent.
HeartbeatsSent	Number of heartbeats sent.
NotificationInterval	How often how often (in milliseconds) notifications are sent.
HeartbeatInterval	How often (in milliseconds) heartbeat notifications are sent.
BatchSize	Batch size. (The maximum number of events that the active batch size can increase to.)
ActiveBatchSize	The current batch size. (The current number of events to include in a single notification message.) The batch size is automatically adjusted based on network throughput and system performance. Its value never exceeds the specified batch size.
AllowedCoordinators	List of coordinators permitted to send events.
LastCoordinator	The coordinator that is sending events. If the subscription is disabled, this is the last coordinator sending the events.
IncludeO365AADDetails	Identifies whether or not the additionalDetails field with the raw JSON string is included for Office 365 and Azure Active Directory events.
TIsEnabled	Specifies whether TLS encryption is enabled.
SyslogFormat	Specifies the message format (LEEF or CEF).

Set-CASyslogEventSubscription

Use this command to modify a Syslog subscription.

Table 2. Available parameters


Parameter	Description
-Connection	A connection obtained by using the Connect-CAClient command. See the Change Auditor Command Guide for details.
-Host (Optional)	Specifies the IP address or host name of the computer where the Syslog server is installed.
-Port (Optional)	The the port number for the Syslog server.
-TIsEnabled (Optional)	Specifies whether TLS encryption is enabled.
-SyslogFormat (Optional)	Specifies the message format (LEEF or CEF).
-Subscription	The PSCASyslogEventSubscriptionStatus object that corresponds to the subscription to modify. This parameter is required if the SubscriptionId parameter is not specified.
-SubscriptionId	The ID of the subscription to modify. This parameter is required if the Subscription parameter is not specified. Use the Get-CASyslogEventSubscriptions command to find the ID.
-BatchSize (Optional)	Specifies the maximum number of events to include in a single notification. The default is 10000 events.
-Enabled (Optional)	Specifies whether the subscription is enabled or disabled. By default it is enabled.
-HeartbeatUrl (Optional)	Specifies where (URL) to send heartbeat notifications. NOTE: If no value is specified, a heartbeat notification is not sent.
-NotificationInterval (Optional)	Specifies how often (in milliseconds) notifications are sent to the computer where the Syslog server is installed. By default this is set to 0 which results in a continuous stream of events.
-HeartbeatInterval (Optional)	Specifies how often (in milliseconds) heartbeat notifications are sent to the HeartbeatUrl. By default, this is set to every 5 minutes. Setting this to 0 disables the heartbeat notifications.
-AllowedCoordinators (Optional)	Specifies the DNS or NetBIOS name of the coordinators permitted to send events. By default, any coordinator can send the events. NOTE: The list order does not determine which coordinator is selected to send events.
-Subsystems (Optional)	Specifies an array of event subsystems from which to send events. This can be single or multiple subsystems. NOTE: To obtain an array of subsystems, use the Get-CAEventExportSubsystems command and filter the list to specify the required subsystems. NOTE: The subsystems specified override the current subsystems included in the subscription.
-IncludeO365AADDetails (Optional)	Specifies whether to include the raw JSON event details provided by Microsoft. When set to true, the event will include a field named additionalDetails, containing the raw JSON string for Office 365 and Azure Active Directory events. When set to false, the additionalDetails field is not included. By default, this is set to true.

Example: Disable a subscription

Set-CASyslogEventSubscription -Connection $connection -SubscriptionId $SubscriptionId -Enabled $false

Example: Edit the subsystems included in a subscription

$newSubsystems = Get-CAEventExportSubsystems -Connection $connection | ? { $_.DisplayName -eq "File System" -or $_.DisplayName -eq "Active Directory" }

Set-CASyslogEventSubscription -Connection $connection -SubscriptionId cd87b774-8e65-46e1-8520-da478c60c4c3 -Subsystems $newSubsystems

Remove-CASyslogEventSubscription

Use this command to remove a subscription.

Table 21. Available parameters


Parameter	Description
-Connection	A connection obtained by using the Connect-CAClient command. See the Change Auditor Command Guide for details.
-Subscription	The PSCASyslogEventSubscriptionStatus object that corresponds to the subscription to remove. This parameter is required if the SubscriptionId parameter is not specified.
-SubscriptionId	The ID of the subscription to remove. This parameter is required if the Subscription parameter is not specified. Use the Get-CASyslogEventSubscriptions command to find the ID.

Example: Remove a subscription

Remove-CASyslogEventSubscription -Connection $connection -SubscriptionId $subscriptionId

Managing a Microsoft Sentinel integration

To send the rich events gathered by Change Auditor to Microsoft Sentinel, you need to create an event subscription with Change Auditor. The subscription contains information about where to send the notifications and heartbeats and the event subsystems to include.


	NOTE: When enabled, heartbeat notifications are sent to the Heartbeat_ChangeAuditor_CL log in Microsoft Sentinel where you can query and alert on them if required. The following Azure Log Analytics KQL query example, returns a list of servers missing heartbeats in the last 10 minutes where the servers have been active at some point in the last 24 hours. Heartbeat_ChangeAuditor_CL \| where timeSent_t >= ago(24h) \| project timeSent_t, sender_s \| order by timeSent_t desc \| partition by sender_s ( top 1 by timeSent_t ) \| where timeSent_t < ago(10m) \| project sender_s