Files may be copied from one system to another to stage adversary tools or other files over the course of an operation. Files may be copied from an external adversary-controlled system through the Command and Control channel to bring tools into the victim network or onto the victim’s device.
Applications with network connections to unknown domains or IP addresses could be further scrutinized to detect unauthorized file copying. Further, some application vetting services may indicate precisely what content was requested during application execution.
Downloading remote files is common application behavior and is therefore typically undetectable to the end user.