Hardware Additions

What the technique is

Adversaries may physically 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 points to an existing network, and others.

What MITRE says you would watch

• AN0185

  Chain: (1) a new external device is recognized by Windows (USB/Thunderbolt/PCIe) or a new block device appears; (2) within a short window, the same user/session spawns processes or the OS mounts a new volume; (3) optional follow-on activity such as HID keystroke injection, DMA driver load, or new network interface MAC on DHCP. Correlate Security EID 6416 / Kernel-PnP with sysmon and DHCP/network metadata.

• AN0186

  Chain: (1) udev / kernel logs show hot-plug (USB/Thunderbolt/PCIe); (2) block device created by udisks/diskarbitration; (3) optional: new network interface or DHCP lease observed. Correlate /var/log/messages|syslog, auditd SYSCALL open/creat on /dev, and DHCP/Zeek.

• AN0187

  Chain: (1) unified logs report IOUSBHost/IOThunderbolt device arrival; (2) diskarbitrationd attaches a new volume; (3) optional: config profile manipulation or new network interface MAC obtains a lease. Correlate unifiedlogs (subsystems: IOUSBHost, IOKit, diskarbitrationd), FSEvents, and DHCP/Zeek.