Microsoft Sentinel as a SIEM solution

What is the role of a SIEM?

The role of a Security Information and Event Management (SIEM) system is to provide real-time visibility into security events and threats across an organization's network and systems. The primary functions of a SIEM include:

Log collection: A SIEM collects security event logs from various sources, such as network devices, servers, and endpoints. These logs are analyzed to detect patterns and anomalies that may indicate a security threat.

Event correlation: The SIEM correlates events from various sources to identify potential security incidents. By analyzing events together, the SIEM can identify patterns of behavior that may indicate a security threat.

Threat detection and response: The SIEM uses threat intelligence and other techniques to detect known and unknown threats. When a threat is detected, the SIEM alerts security analysts to investigate and respond to the incident.

Compliance monitoring: SIEM systems can help organizations meet regulatory and compliance requirements by monitoring for specific events or activities that may be required by compliance regulations.

Reporting and analysis: SIEM systems provide detailed reporting and analysis capabilities, which allow security analysts to better understand security incidents and identify areas for improvement in their security posture.

Introducing Microsoft Sentinel

Microsoft Sentinel, also known as Azure Sentinel, is a cloud-native security information and event management (SIEM) service offered by Microsoft. It provides intelligent security analytics and threat intelligence across the enterprise by collecting data from various sources such as network devices, endpoints, cloud resources, and applications.

With Microsoft Sentinel, security teams can quickly detect and respond to security threats by leveraging machine learning and artificial intelligence (AI) technologies. The service provides a centralized dashboard that offers visibility into security incidents, and it also integrates with other Microsoft security services such as Microsoft Defender for Endpoint, Microsoft Cloud App Security, and Microsoft Information Protection to provide a holistic view of the organization's security posture.

Common usage scenarios of Microsoft Sentinel

Threat detection and response: Sentinel provides a single dashboard for security analysts to investigate security incidents, identify root causes, and respond to threats quickly and efficiently.

Security automation and orchestration: Sentinel integrates with Microsoft's security tools and other third-party solutions to automate and orchestrate security operations, reducing manual effort and increasing efficiency.

Compliance and audit reporting: Sentinel can help organizations meet compliance requirements by providing reporting and audit trails that document security events and incidents.

Cloud security monitoring: Sentinel is designed for monitoring cloud-based applications and infrastructure, making it well-suited for organizations that use cloud services or have a hybrid cloud environment.

Advanced threat hunting: Sentinel provides advanced analytics and machine learning capabilities, which can help organizations identify and respond to complex threats that may be difficult to detect with traditional security tools.

Microsoft Sentinel prerequisites

Azure subscription: Microsoft Sentinel is a cloud-based service, so an Azure subscription is required to use it.

Log sources: Sentinel requires log sources to provide data for analysis. The logs can come from various sources, including Azure services, on-premises infrastructure, and third-party solutions.

Log ingestion: Organizations need to configure log ingestion from various sources into Sentinel. The logs can be ingested using various methods, including agents, APIs, and connectors.

Data connectors: Organizations need to configure data connectors to bring in log data from various sources. Sentinel has many built-in connectors, but custom connectors may also need to be created.

Security policies: Sentinel requires security policies to define how the service should analyze and respond to security events. These policies should be tailored to the organization's specific security needs.

Access controls: Organizations need to configure access controls to ensure that only authorized personnel can access Sentinel and its data.

Network connectivity: Organizations need to ensure that their network infrastructure allows for the necessary traffic to flow between their environment and Azure.

Microsoft Sentinel licensing

Licensing for Microsoft Sentinel is based on the amount of data ingested into the service.

Microsoft Sentinel offers two tiers of pricing:

Pay-as-you-go: This pricing model charges based on the volume of data ingested into the service, with no upfront commitment. The cost is based on the amount of data ingested per day, measured in gigabytes (GB) per day.

Capacity Reservation: This pricing model allows customers to reserve a certain amount of capacity for a one or three-year term. Customers who reserve capacity receive a discount on the pay-as-you-go pricing.

Additionally, Microsoft offers some free data ingestion sources that don't count against the overall data volume used to calculate billing. These sources include Azure Active Directory, Azure Activity Logs, and Microsoft 365 audit logs.

Microsoft Sentinel is included in certain Azure subscription plans, such as Azure Defender for IoT and Azure Defender for Servers, and customers with these subscriptions may be entitled to free or discounted access to Sentinel.

Microsoft Sentinel, a real replacement for an on-premises SIEM?

Microsoft Sentinel can be considered as a real replacement for an on-premises SIEM in some cases, but it ultimately depends on the specific needs and requirements of an organization.

There are several benefits to using a cloud based SIEM like Microsoft Sentinel, such as:

Scalability: Cloud-based SIEMs can easily scale up or down depending on the needs of the organization.

Cost: Cloud-based SIEMs can be more cost-effective than on-premises solutions, as they do not require the same level of hardware and maintenance expenses.

Maintenance: Cloud-based SIEMs are maintained by the vendor, which can alleviate the burden of maintenance and updates from the organization.

However, there may be certain scenarios where an on-premises SIEM is preferred, such as:

Compliance requirements: Some compliance regulations may require certain data to be kept on-premises.

Network restrictions: Organizations with strict network restrictions may not be able to use a cloud-based solution.

Data control: Some organizations may prefer to have complete control over their data, which may not be possible with a cloud-based solution.

Ultimately, the decision to use Microsoft Sentinel or an on-premises SIEM depends on the specific needs and requirements of the organization and should be carefully evaluated before deciding.

Microsoft Sentinel factors for success

There are several factors to consider having a successful Microsoft Sentinel deployment:

Planning: Adequate planning is crucial for a successful deployment. This includes identifying the scope of the deployment, defining the data sources that need to be ingested, setting up alerts and rules, and defining incident response processes.

Data Sources: The success of Sentinel deployment depends heavily on the data sources that are ingested into it. It is important to identify the relevant data sources and ensure that they are properly configured and accessible.

Integration: Sentinel can integrate with a variety of Microsoft and third-party tools, such as Azure Security Center, Microsoft Defender, and Office 365. It is important to identify the integration points and ensure that they are properly configured.

Automation: Sentinel provides automation capabilities through playbooks, which can be used to automate incident response processes. It is important to identify the processes that can be automated and develop the appropriate playbooks.

Alert Management: Sentinel generates alerts based on rules and machine learning models. It is important to ensure that the alerts are properly managed and acted upon in a timely manner.

User Adoption: Sentinel can only be successful if it is adopted by the users. It is important to provide adequate training and support to the users to ensure that they are comfortable with the tool and can use it effectively.

Continuous Improvement: Sentinel should be continuously monitored and improved to ensure that it is providing value and meeting the needs of the organization. This includes regularly reviewing the alerts and rules, updating the playbooks, and incorporating feedback from users.

What could be issues related to a Microsoft Sentinel deployment?

Data ingestion issues: One of the biggest challenges of using Sentinel is ensuring that the right data is being ingested. Ingestion can fail if the data is in the wrong format or if there is a problem with the connection between the data source and Sentinel.

Alert fatigue: Sentinel generates a lot of alerts, and it's important to tune them to reduce the noise and focus on the most important alerts. Failure to do so can result in alert fatigue, where analysts become overwhelmed with alerts and start to ignore them.

Lack of customization: Although Sentinel comes with many built-in analytics rules and templates, it may not cover all the scenarios specific to your organization. To get the most out of Sentinel, you need to customize it to fit your organization's needs.

Difficulty with query language: Sentinel uses a proprietary query language called Kusto, which can be difficult to learn and use. This can be a barrier for analysts who are not familiar with the language and require additional training.

Integration challenges: Sentinel integrates with a wide range of data sources, but some integrations can be more challenging than others. Some data sources may require additional configuration or custom connectors, which can be time-consuming and complex.

Cost: Sentinel is a cloud-based service and is billed on a consumption basis, which means that costs can add up quickly. It's important to have a good understanding of your organization's data volume and usage patterns to avoid unexpected costs.

Dependency on the cloud: Since Sentinel is a cloud-based service, it is dependent on the availability and performance of the cloud infrastructure. Any disruption or downtime in the cloud can affect the availability and performance of Sentinel.

Compliance issues: Sentinel is subject to various compliance requirements, such as GDPR and HIPAA. It's important to understand these requirements and ensure that Sentinel is configured to meet them. Failure to do so can result in regulatory fines and other legal issues.

What permissions related to the configuration of Microsoft Sentinel?

Global Administrator: This is the highest level of permission in Azure AD, and it allows you to manage all aspects of Azure, including subscription and resource management.

Security Administrator: This permission allows you to manage security policies, view security reports, and manage security alerts in Azure.

Security Reader: This permission allows you to view security policies and reports, but you cannot make any changes to them.

Contributor: This permission allows you to manage resources in Azure, but you cannot view or manage security policies and reports.

Log Analytics Contributor: This permission allows you to manage log data in Log Analytics workspaces, which are used by Microsoft Sentinel to collect and store security data.

Storage Blob Data Contributor: This permission allows you to manage storage accounts in Azure, which are used to store log data collected by Microsoft Sentinel.

Conclusion

In today’s landscape, it is imperative to have a comprehensive security solution that can provide real-time threat detection and response. This is where Microsoft Sentinel comes in.

Microsoft Sentinel is a cloud-native security information and event management (SIEM) solution that uses advanced artificial intelligence and machine learning to detect and respond to security threats in real-time. With Sentinel, you can monitor your entire IT infrastructure, including your on-premises and cloud-based resources, from a single console.

Interested in learning more? How about enrolling to our course that is exploring Microsoft Sentinel in depth? Browse the Microsoft Certified: Security Operations Analyst Associate (SC200) training to get more details on how the implementation of Microsoft Sentinel can be a success for your organization.