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Splunk Lantern

Azure Kubernetes Service accounts with failed or forbidden status

You want to investigate failed or forbidden status accounts on your network to determine if they represent a threat. 

Procedure

  1. Ensure that you have configured Kube-Audit data diagnostics.
  2. Run the following search. You can optimize it by specifying an index and adjusting the time range.
sourcetype=mscs:storage:blob:json category=kube-audit 
| spath input=properties.log 
| search user.groups{}=system:serviceaccounts*  responseStatus.reason=Forbidden 
| table  sourceIPs{} user.username userAgent verb responseStatus.reason responseStatus.status properties.pod objectRef.namespace  

Search explanation

The table provides an explanation of what each part of this search achieves. You can adjust this query based on the specifics of your environment.

Splunk Search Explanation

sourcetype:mscs:storage:blob:json 

Search only the source type mscs:storage:blob:json. 

category=kube-audit

Search the data source kube-audit from the diagnostic logs in Azure Cloud services.

| spath input=properties.log 

Extract fields from the properties Kube-Audit log.

| search user.groups{}=system:serviceaccounts*  responseStatus.reason=Forbidden 

Search for service accounts with a response status of Forbidden.

| table  sourceIPs{} user.username userAgent verb responseStatus.reason responseStatus.status properties.pod objectRef.namespace  

Display the results in a table with columns in the order shown.

Next steps

You can extend this search by using top or rare operators to find trends or rarities in failure status, user agents, source IP addresses, and request URIs. Note that this search can give false positives as there might be inherent issues with authentications and permissions at cluster.

For additional information about this search, such as its applicability to common frameworks and standards, see this project on GitHub for AWS, Azure, or GCP.

Finally, you might be interested in other processes associated with the Monitoring Kubernetes sensitive object access use case.