Adversaries may introduce computer accessories, networking hardware, or other computing devices into a system or network that can be used as a vector to gain access. Rather than just connecting and distributing payloads via removable storage (i.e. Replication Through Removable Media), more robust hardware additions can be used to introduce new functionalities and/or features into a system that can then be abused.
While public references of usage by threat actors are scarce, many red teams/penetration testers leverage hardware additions for initial access. Commercial and open source products can be leveraged with capabilities such as passive network tapping, network traffic modification (i.e. Adversary-in-the-Middle), keystroke injection, kernel memory reading via DMA, addition of new wireless access to an existing network, and others.
DarkVishnya used Bash Bunny, Raspberry Pi, netbooks or inexpensive laptops to connect to the company’s local network.
|M1035||Limit Access to Resource Over Network||
Establish network access control policies, such as using device certificates and the 802.1x standard.  Restrict use of DHCP to registered devices to prevent unregistered devices from communicating with trusted systems.
|M1034||Limit Hardware Installation||
Block unknown devices and accessories by endpoint security configuration and monitoring agent.
|ID||Data Source||Data Component||Detects|
|DS0015||Application Log||Application Log Content||
Configuration management databases (CMDB) and other asset management systems may help with the detection of computer systems or network devices that should not exist on a network.
Monitor for newly constructed drives or other related events associated with computer hardware and other accessories (especially new or unknown) being connected to systems. Endpoint sensors may be able to detect the addition of hardware via USB, Thunderbolt, and other external device communication ports.
|DS0029||Network Traffic||Network Traffic Flow||
Monitor for network traffic originating from unknown/unexpected hardware devices. Local network traffic metadata (such as source MAC addressing) as well as usage of network management protocols such as DHCP may be helpful in identifying hardware.