The 'Spike in File Writes' analytic rule is designed to detect abnormal increases in the number of files written to a specific host, potentially indicative of malicious activity such as ransomware encryption or unauthorized data exfiltration. This rule utilizes the Endpoint.Filesystem data model, focusing specifically on 'created' file actions within a one-hour time frame. By analyzing historical averages and standard deviations over the previous 24 hours, sudden spikes are identified as outliers that warrant further investigation. If a spike is detected, it may signal significant risks including data loss and system compromise. The rule implements a data query using Splunk's tstats command to calculate file write counts and applies statistical measures to determine abnormal activity. Implementation requires prior population of the Endpoint file-system data model, typically gathered from Endpoint Detection and Response (EDR) systems or Sysmon. While effective, be cautious of known false positives during events of high file activity, such as software installations or bulk file operations, which may trigger alerts without malicious intent.