The 'NullSessionPipe Registry Modification' detection rule is designed to monitor modifications to the NullSessionPipe registry setting in Windows, which allows certain named pipes to be accessed without authentication. This capability can be exploited by adversaries for lateral movement within a network. The rule checks for changes in the registry path pertaining to named pipes that could indicate an attempt to make them accessible to anyone, which may suggest preparatory actions for unauthorized access or movement across systems. A specified query using EQL (Event Query Language) is utilized to detect these changes based on defined conditions, including the type of event and the registry path. The rule's implementation requires several data indices from endpoint and registry logs, ensuring comprehensive monitoring across various sources. The investigation guide emphasizes analyzing registry change details, correlating timestamps with other security events, and assessing risks related to the modifications. Potential responses include isolating affected systems, reverting unauthorized changes, and performing thorough scans for malware.