Outbound transfer behavior is network activity that suggests data is leaving an environment. It can include large uploads, repeated connections to cloud storage, unusual use of FTP, HTTPS, DNS tunneling, or other traffic patterns that do not match normal business activity. The behavior is not proof of theft by itself, but it is a useful signal that sensitive files may be moving toward an external destination.
Security teams watch for this pattern because it often appears during data exfiltration, backup abuse, or unauthorized sync tools. Defenders compare the traffic against baselines, identity context, and endpoint telemetry to decide whether the transfer is legitimate or malicious. In attacks, outbound transfer behavior may follow initial compromise and lateral movement, when an intruder tries to copy data out before containment. In defenses, alerts from proxies, firewalls, CASB, DLP, and SIEM systems help investigators confirm scope, preserve evidence, and stop further loss.