An engineer received a ticket to investigate a potentially malicious file detected by a malware...

An engineer received a ticket to investigate a potentially malicious file detected by a malware scanner that was trying to execute multiple commands. During the initial review, the engineer discovered that the file was created two days prior. Further analyses show that the file was downloaded from a known malicious domain after a successful phishing attempt on an asset owner. At which phase of the Cyber Kill Chain was this attack mitigated?