How do you monitor and audit Kerberos SSO activity on Windows?

1 Enable Kerberos auditing

To start, you must activate Kerberos auditing on your domain controllers and servers hosting applications or resources you want to monitor. You can use Group Policy or Auditpol command for this. Additionally, you must configure the audit policy for Kerberos service ticket operations, Kerberos authentication service, Kerberos ticket-granting ticket operations, and Kerberos distribution service events. These events will create logs containing information about users, services, tickets, and errors related to Kerberos SSO.

2 Analyze Kerberos logs

Analyzing the Kerberos logs stored in the Security event log on your domain controllers and servers is the next step. You can use Event Viewer, PowerShell, or third-party tools to filter, sort, and query the logs. The logs can reveal information such as the source and destination of the Kerberos requests and responses, the type and duration of the Kerberos tickets, the success or failure of the Kerberos authentication and authorization, and any error codes or messages that indicate problems with Kerberos SSO. By examining these logs, you can troubleshoot issues, uncover anomalies, and check if your security policies are being followed.

3 Configure Kerberos alerts

The third step is to set up Kerberos alerts that notify you of any significant or suspicious events related to Kerberos SSO. You can use Windows Server Manager, Task Scheduler, or third-party tools to create and manage these alerts, customizing the triggers, actions, and conditions based on the event IDs, error codes, or keywords in the Kerberos logs. For instance, you could set up alerts for when a user requests a Kerberos ticket for an unauthorized service or resource; a service or resource rejects a valid Kerberos ticket from a user; a Kerberos ticket expires or is revoked before its expected lifetime; or a Kerberos ticket is forged, modified, or replayed by an attacker. By configuring these alerts, you can ensure that any incidents or risks related to Kerberos SSO are quickly and effectively addressed.

4 Review Kerberos reports

Reviewing Kerberos reports is the fourth step in evaluating the efficiency and effectiveness of Kerberos SSO on your Windows network. Windows Performance Monitor, PowerShell, or third-party tools can be used to generate and export these reports. You can customize the reports based on the time range, scope, and metrics you want to measure. For instance, you can create reports to monitor the number and percentage of Kerberos tickets issued, renewed, and used; the average and maximum lifetime and size of tickets; the distribution and trend of errors and failures; and the performance and availability of the Kerberos service and key distribution center. By doing so, you can identify areas for improvement or optimization.

5 Implement Kerberos best practices

The fifth step is to implement Kerberos best practices that enhance the security and reliability of Kerberos SSO on your Windows network. Microsoft and other sources recommend configuring and maintaining your Kerberos settings and policies. These include using strong encryption and hashing algorithms for Kerberos tickets and keys, domain-based service accounts and managed service accounts for Kerberos services, constrained delegation and resource-based constrained delegation for cross-domain and cross-forest Kerberos scenarios, smart cards or certificates for multifactor authentication with Kerberos, as well as monitoring and updating the Kerberos key distribution center and the domain controller roles. By following these best practices, you can protect yourself from common threats and vulnerabilities related to Kerberos SSO.

6 Here’s what else to consider

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