ATT&CK analytic guidance
Unusual or unauthorized external remote access attempts (e.g., RDP, VPN, Citrix) → repeated failed logins followed by a successful session from uncommon geolocations or outside business hours → subsequent internal lateral movement or data exfiltration activities.
Repeated SSH, VPN, or RDP gateway authentication attempts from external IPs → subsequent successful logon → remote shell or lateral movement activity (e.g., scp/sftp).
Unexpected inbound or outbound VNC/SSH/Screen Sharing connections from external sources → repeated failed logins followed by success → remote interactive sessions or abnormal file transfers.
Connections to exposed container services (e.g., Docker API, Kubernetes API server) from unauthorized external IPs → abnormal container creation/start → lateral activity within cluster nodes.