Special thanks to @Ofer_Shezaf and @Alp Babayigit that collaborating with me on this blog post.
In the blog post we will introduce a solution which uses Logic Apps to automatically attach evidence to Azure Sentinel alerts and send them to an Event Hub that can be consumed by a 3rd party SIEMs and Ticketing Systems.
Using Sentinel alongside a 3rd party SIEM and ticketing systems
From our customers engagements we learned that sometimes customers prefer to maintain their existing SIEM alongside Azure Sentinel.
Among the reasons for doing so are:
- Using Azure Sentinel as a cloud SIEM alongside the existing SIEM to monitor on-prem workloads.
- Using both during the transition period.
In addition, customers often use a ticketing system, such as Service Now or JIRA to manage incidents at the SOC and need to forward alert information to those systems.
Traditionally, customers forwarded alerts from Azure Sentinel to their existing SIEM or ticketing systems using the Graph Security API. You can do so for Splunk, QRadar, Service Now or any other SIEM or Ticketing System that supports Event Hub ingestion.
Azure Sentinel supporting evidence
However, in a side by side deployment, alerts from one platform need to be sent to the other to enable a single pane of glass for the analyst. To ensure efficient triaging on the primary pane of glass, the alerts have to include enough supporting information. When the 3rd Party SIEM or ticketing system is used as the primary pane of glass, this translates to sending both Azure Sentinel alerts and their supporting events to this system.
When you press “Events”, you are redirected to the “Logs” screen to view the supporting events relevant to the alert. Those can be, but are not necessarily, raw events collected by Azure Sentinel. Instead, the alert rule determines what to present as supporting events. Learn more about how a rule controls the supporting evidence in the Azure Sentinel KQL lab (YouTube, deck) and the Azure Sentinel rule writing Webinar (YouTube, deck).
As an example, the following alert rule taken from the KQL Lab uses the summarize and extend keywords to produce just the data relevant to the detected anomalies:
Forwarding alerts with supporting events to an Event Hub
In this article, we demonstrate how to use Azure sentinel SOAR capability and leverage a Logic App playbook to send alerts with their associated supporting events to a 3rd party SIEM.
The playbook, available here, works as follows:
- The playbook triggers when an alert is created (1), this can be done automatically for each alert when it triggers, or on-demand by an analyst.
- Parse JSON actions are used throughout the playbook to transform JSON objects received to the format expected in subsequent steps.
- Query the workspace for the supporting events (2). Note that the query to fetch the supporting events is included as part of the alert extended properties.
- Send the enriched alert to an Event Hub (3).
