What is security incident and event management (SIEM)?

A SIEM system is a tool that an organization uses to collect, analyze, and perform security operations on its computer systems. Those systems can be hardware appliances, applications, or both.

In its simplest form, a SIEM system enables you to:

• Collect and query logs.
• Do some form of correlation or anomaly detection.
• Create alerts and incidents based on your findings.

A SIEM system might offer functionality such as:

• Log management: The ability to collect, store, and query the log data from resources within your environment.

• Alerting: A proactive look inside the log data for potential security incidents and anomalies.

• Visualization: Graphs and dashboards that provide visual insights into your log data.

• Incident management: The ability to create, update, assign, and investigate incidents that have been identified.

• Querying data: A rich query language, similar to that for log management, that you can use to query and understand your data.

What is Microsoft Sentinel?

Azure Sentinel is a cloud-native SIEM system that a security operations team can use to:

• Get security insights across the enterprise by collecting data from virtually any source.
• Detect and investigate threats quickly by using built-in machine learning and Microsoft threat intelligence.
• Automate threat responses by using playbooks and by integrating Azure Logic Apps.

Unlike with traditional SIEM solutions, to run Microsoft Sentinel, you don't need to install any servers either on-premises or in the cloud. Microsoft Sentinel is a service that you deploy in Azure. You can get up and running with Sentinel in just a few minutes in the Azure portal.

Microsoft Sentinel is tightly integrated with other cloud services. Not only can you quickly ingest logs, but you can also use other cloud services natively (for example, authorization and automation).

Microsoft Sentinel helps you enable end-to-end security operations including collection, detection, investigation, and response:

How Microsoft Sentinel works

As you've already learned, Microsoft Sentinel helps you enable end-to-end security operations. It starts with log ingestion and continues through to automated response to security alerts.

Here are the key features and components of Microsoft Sentinel.

Data connectors

The first thing to do is to have your data ingested into Microsoft Sentinel. Data connectors enable you to do just that. You can add some services, such as Azure activity logs, just by selecting a button. Others, such as syslog, require a little configuration. There are data connectors that cover all scenarios and sources, including but not limited to:

• syslog
• Common Event Format (CEF)
• Trusted Automated eXchange of Indicator Information (TAXII) (for threat intelligence)
• Azure
• AWS services

Log retention

After it's been ingested into Microsoft Sentinel, your data is stored by using Log Analytics. The benefits of using Log Analytics include the ability to use the Kusto Query Language (KQL) to query your data. KQL is a rich query language that gives you the power to dive into and gain insights from our data.

Workbooks

You use workbooks to visualize your data within Microsoft Sentinel. Think of workbooks as dashboards. Each component in the dashboard is built by using an underlying KQL query of your data. You can use the built-in workbooks within Microsoft Sentinel, edit them to meet your own needs, or create your own workbooks from scratch. If you've used Azure Monitor workbooks, this feature will be familiar to you because it's Sentinel's implementation of Monitor workbooks.

Analytics alerts

So far, you have your logs and some data visualization. Now it would be great to have some proactive analytics across your data, so you're notified when something suspicious occurs. You can enable built-in analytics alerts within your Sentinel workspace. There are various types of alerts, some of which you can edit to your own needs. Other alerts are built on machine-learning models that are proprietary to Microsoft. You can also create custom, scheduled alerts from scratch.

Threat hunting

We won't dive deeply into threat hunting, however, if SOC analysts need to hunt for suspicious activity, there are some built-in hunting queries that they can use. Analysts can also create their own queries. Sentinel also integrates with Azure Notebooks. It provides example notebooks for advanced hunters who want to use the full power of a programming language to hunt through their data.

Incidents and investigations

An incident is created when an alert that you've enabled is triggered. In Microsoft Sentinel, you can do standard incident management tasks like changing status or assigning incidents to individuals for investigation. Microsoft Sentinel also has investigation functionality, so you can visually investigate incidents by mapping entities across log data along a timeline.

Automation playbooks

With the ability to respond to incidents automatically, you can automate some of your security operations and make your SOC more productive. Microsoft Sentinel integrates with Azure Logic Apps, enabling you to create automated workflows, or playbooks, in response to events. This functionality could be used for incident management, enrichment, investigation, or remediation. These capabilities are often referred to as security orchestration, automation, and response (SOAR).