Behavior-chain detection for T1133 External Remote Services across Windows, Linux, macOS, Containers

ID: DET0354
Domains: Enterprise
Analytics: AN1004, AN1005, AN1006, AN1007
Version: 1.0
Created: 21 October 2025
Last Modified: 21 October 2025

Analytics

AN1004

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.

Log Sources
Data Component Name Channel
User Account Authentication (DC0002) WinEventLog:Security EventCode=4624, 4625
Application Log Content (DC0038) WinEventLog:Application VPN, Citrix, or remote access gateway logs showing external IP addresses
Network Connection Creation (DC0082) WinEventLog:Sysmon EventCode=3
Mutable Elements
Field Description
BusinessHours Normal business hours for logon activity.
KnownRemoteIPs List of approved external IPs or VPN endpoints.
FailedLogonThreshold Number of failed logons before raising suspicion (e.g., >5).
GeoIPWhitelist Geographic regions allowed for remote access.
TimeWindow Time window to correlate failed attempts and success (e.g., 15m).

AN1005

Repeated SSH, VPN, or RDP gateway authentication attempts from external IPs → subsequent successful logon → remote shell or lateral movement activity (e.g., scp/sftp).

Log Sources
Data Component Name Channel
Logon Session Metadata (DC0088) auditd:SYSCALL ssh logins or execve of remote commands
Application Log Content (DC0038) NSM:Connections Failed password or accepted password for SSH users
Network Connection Creation (DC0082) NSM:Flow connection: Inbound connections to SSH or VPN ports
Mutable Elements
Field Description
KnownSSHClients Legitimate IPs or client fingerprints for SSH/VPN.
FailedLogonThreshold Number of failed SSH logins to trigger alert.
TimeWindow Correlation window for failed attempts and success.

AN1006

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.

Log Sources
Data Component Name Channel
Logon Session Metadata (DC0088) macos:unifiedlog Remote login (ssh) or screen sharing authentication attempts
Network Connection Creation (DC0082) macos:unifiedlog Inbound connections to VNC/SSH ports
Network Traffic Flow (DC0078) PF:Logs External traffic to remote access services
Mutable Elements
Field Description
KnownVNCServers List of approved VNC/SSH sources.
TimeWindow Time correlation between failed attempts and success.

AN1007

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.

Log Sources
Data Component Name Channel
Application Log Content (DC0038) ApplicationLog:API Docker/Kubernetes API access from external sources
Logon Session Metadata (DC0088) kubernetes:audit Unauthorized container creation or kubelet exec logs
Network Connection Creation (DC0082) NSM:Flow External access to container ports (2375, 6443)
Mutable Elements
Field Description
AllowedCIDRs Approved external IP ranges for container APIs.
TimeWindow Correlation window for API calls and container starts.