This detection rule identifies when a program attempts to alter the default file association for any file extension to an executable program using the Windows 'assoc' command. The default file association determines which application is used to open files with specific extensions, and modifying this association can be a technique employed by malicious actors to execute arbitrary programs when users attempt to open what they might expect to be safe file types. The rule monitors for process creation events, specifically focusing on instances where 'cmd.exe' is invoked with command-line arguments indicating an execution of the 'assoc' command, followed by attempts to set a file extension to 'exefile'. The detection logic involves filtering specific command-line inputs to assess potential tampering. It is vital for security systems to detect such changes, as it may signify malicious persistence mechanisms or exploitation tactics.