The rule 'Unusual Web Config File Access' is designed to detect anomalous access to the web.config file in Windows environments. The web.config file is crucial as it holds sensitive information such as database connection strings and machine key validation/decryption keys, which are often targeted by attackers. Unauthorized access to this file can lead to information leakage, enabling malicious actors to execute payloads or persist Remote Code Execution (RCE) attacks on the web server through the manipulation of __________VIEWSTATE requests or pivot attacks to the SQL server via exposed connection strings. The detection rule utilizes specific queries within Elastic's logging system, focusing on events categorized as file accesses and filtered to identify attempts to open the web.config file within VirtualDirectories. A medium severity risk score of 47 indicates that while the occurrence is notable, further validation is required for any alerts raised against this rule.