Adversaries may leverage traffic mirroring in order to automate data exfiltration over compromised infrastructure. Traffic mirroring is a native feature for some devices, often used for network analysis. For example, devices may be configured to forward network traffic to one or more destinations for analysis by a network analyzer or other monitoring device. 
Adversaries may abuse traffic mirroring to mirror or redirect network traffic through other infrastructure they control. Malicious modifications to network devices to enable traffic redirection may be possible through ROMMONkit or Patch System Image.
Many cloud-based environments also support traffic mirroring. For example, AWS Traffic Mirroring, GCP Packet Mirroring, and Azure vTap allow users to define specified instances to collect traffic from and specified targets to send collected traffic to.
|M1041||Encrypt Sensitive Information||
Ensure that all wired and/or wireless traffic is encrypted appropriately. Use best practices for authentication protocols, such as Kerberos, and ensure web traffic that may contain credentials is protected by SSL/TLS.
|M1018||User Account Management||
In cloud environments, ensure that users are not granted permissions to create or modify traffic mirrors unless this is explicitly required.
|ID||Data Source||Data Component||Detects|
|DS0029||Network Traffic||Network Connection Creation||
Monitor for newly constructed network connections that are sent or received by abnormal or untrusted hosts.
|Network Traffic Flow||
Monitor and analyze network flows associated to protocol(s) that do not follow the expected protocol standards and traffic flows (e.g extraneous packets that do not belong to established flows, or gratuitous or anomalous traffic patterns). Consider analyzing newly constructed network connections that are sent or received by untrusted hosts, unexpcted hardware devices, or other uncommon data flows.