Detection Strategy for Traffic Duplication via Mirroring in IaaS and Network Devices

Technique Detected:  Traffic Duplication | T1020.001

ID: DET0403
Domains: Enterprise
Analytics: AN1131, AN1132
Version: 1.0
Created: 21 October 2025
Last Modified: 21 October 2025

Analytics

AN1131

Configuration changes to virtual TAP/mirror policies that forward traffic to unapproved destinations. Detection correlates management plane API calls with mirrored traffic observation.

Log Sources
Data Component Name Channel
Network Traffic Flow (DC0078) AWS:CloudTrail CreateTrafficMirrorSession or ModifyTrafficMirrorTarget
Network Connection Creation (DC0082) AWS:VPCFlowLogs Traffic observed on mirror destination instance
Mutable Elements
Field Description
TimeWindow Detect mirror session creation followed by mirrored traffic within X seconds (e.g., 60s)
MirrorDestinationCIDR Define suspicious or external mirror targets (e.g., non-enterprise ranges)
UserIdentity Flag traffic mirror activity by non-privileged or unexpected IAM roles

AN1132

Unauthorized mirroring sessions initiated on routers/switches (e.g., via monitor session, mirror port) coupled with outbound traffic from mirrored interface to unexpected destinations.

Log Sources
Data Component Name Channel
Network Traffic Flow (DC0078) networkdevice:syslog Config change: CLI/NETCONF/SNMP – 'monitor session', 'mirror port'
Network Connection Creation (DC0082) networkdevice:Flow Traffic from mirrored interface to mirror target IP
Mutable Elements
Field Description
ConfigChangeType Tune based on accepted interface config changes (e.g., audit only mirror session creation)
MirrorDestinationPort Define high-risk ports used for exfil (e.g., 4443, 8443, 2055)
DeviceRole Define whether mirroring is expected on edge vs core vs distribution devices