Estimate the volume of alerts from detection outputs in Splunk Enterprise Security

Effective detection engineering requires balancing thorough threat coverage with manageable alert volumes. Without insight into how many alerts a detection generates, you might create rules that either miss real threats or inundate you with excessive alert noise. By testing and previewing the number of alerts such as findings and intermediate findings, generated by the detection directly in the editor, you can immediately assess the potential impact of the detection. This visibility helps to ensure that new detections deliver actionable, high-quality signals, thereby improving detection quality, reducing false positives, and preventing analyst overload before the detection is ever deployed into the SOC workflow.

You can use the Test panel in the Detection editor of Splunk Enterprise Security to review, test, and predict the volume of search results before turning on your detection. The ability to test detections lets you validate detection performance and fine-tune your rules based on your data, without manually leveraging Search and Reporting feature for testing. For example, you can run your detection over the past 24 hours to see if the number of findings aligns with your expectations, such as the expected 50 findings versus an excessive number of 100,000 findings.

Additionally, the Versioning panel lets you compare detection versions to see how one version performs against another. Simply expand the version you want to evaluate and compare events, findings, and intermediate findings over the same data set, making it easier to validate tuning changes before promoting an updated detection.

You have two options for testing detections: the Findings mode and the Events mode.

The Findings mode includes alerts that are based on specific scheduling and filtering options that you selected when you created the detection. It is based on the detection configuration settings such as cron scheduling, lookback, throttling, conditions, risk entities, SPL query, and so on. The Findings mode narrows down the search results by identifying specific alert types and tunes the detection for greater accuracy. In the Findings mode, you can specify a timeout option from the drop-down, which is the duration of a test. For example, 15 seconds, 30 seconds. 1 minute, and so on. By specifying the length of time that the test runs to gather data, you can balance accuracy and time. The longer you run the detection, the greater is the accuracy of your search results.

The Events mode runs the detection SPL search and includes all the raw events during a specified time frame in the search results. You can review the number of raw events to identify duplicate alerts and potential configuration issues. In the Events mode, you can select lookback periods similar to Splunk Platform searches, ranging from one hour to thirty days. Longer test duration yield more accurate results, while shorter times provide quicker estimates.