parseAttck.Groups: Read MITRE CTI Repository browsing domain directories to extract data from intrusion-set files,
map variables from STIX to ATT&CK model and return tidy data.frame with Group variables.
Description
Read MITRE CTI Repository browsing domain directories to extract data from intrusion-set files,
map variables from STIX to ATT&CK model and return tidy data.frame with Group variables.