The Azure Storage Blob CPK Encryption Detected rule is designed to identify potential ransomware activity by detecting unauthorized access attempts to Azure Storage blobs that are encrypted with Customer-Provided Keys (CPK). The rule is triggered when users attempt to access these blobs but fail due to the absence of the required encryption key, leading to significant implications for data security and access. The analysis of log events related to StorageBlob operations helps identify when files were encrypted, what operations led to the access denials, and any potential credential theft that may have occurred prior. By leveraging Azure MonitorActivity logs and correlating them with known attack patterns, the rule aims to enhance overall cloud security stance by flagging activities that may signify an ongoing ransomware operation.