Detect Hardware Additions in Splunk
Adversaries may physically introduce computer accessories, networking hardware, or other computing devices into a system or network to gain access or expand capabilities. Hardware additions range from passive network taps (Throwing Star LAN Tap) to active keystroke injection devices (USB Rubber Ducky, Bash Bunny, O.MG Cable), rogue wireless access points, DMA attack devices (PCILeech), and fully autonomous compute devices (Raspberry Pi, netbooks) providing persistent network footholds. Unlike purely software-based attacks, hardware additions require physical proximity to target systems and can bypass many software security controls by presenting as trusted peripherals. The DarkVishnya threat group is documented connecting Bash Bunny, Raspberry Pi, and inexpensive netbooks directly to victim organization networks to establish persistent access and conduct internal reconnaissance. Detection relies primarily on monitoring for unexpected device class connections via Windows Plug and Play audit events, correlating new HID device connections with subsequent automated keystroke injection patterns, and identifying new network interfaces with unknown MAC addresses appearing on internal segments.
MITRE ATT&CK
- Tactic
- Initial Access
- Technique
- T1200 Hardware Additions
- Canonical reference
- https://attack.mitre.org/techniques/T1200/
SPL Detection Query
index=wineventlog sourcetype="WinEventLog:Security" EventCode=6416
| rex field=EventData "Name=\"ClassName\">(?P<ClassName>[^<]+)<"
| rex field=EventData "Name=\"DeviceId\">(?P<DeviceId>[^<]+)<"
| rex field=EventData "Name=\"HardwareIds\">(?P<HardwareIds>[^<]+)<"
| rex field=EventData "Name=\"ClassId\">(?P<ClassId>[^<]+)<"
| rex field=EventData "Name=\"SubjectUserName\">(?P<SubjectUserName>[^<]+)<"
| rex field=EventData "Name=\"SubjectDomainName\">(?P<SubjectDomain>[^<]+)<"
| eval IsHIDDevice=if(lower(ClassName)="hidclass", 1, 0)
| eval IsNetworkDevice=if(match(lower(ClassName), "(^net$|wlan|bluetooth|net service)"), 1, 0)
| eval IsKnownPentestVID=if(match(HardwareIds, "(VID_2B04|VID_16D0|VID_2E8A|VID_2341|VID_1B4F|VID_221A|VID_04D8)"), 1, 0)
| eval IsLegitimateVendor=if(match(HardwareIds, "(VID_045E|VID_046D|VID_05AC|VID_413C|VID_03F0|VID_17EF|VID_047D|VID_046A|VID_1B1C|VID_1532|VID_1038|VID_04B3|VID_04CA|VID_0461)"), 1, 0)
| eval IsSuspiciousHID=if(IsHIDDevice=1 AND IsLegitimateVendor=0, 1, 0)
| eval IsUSBNetDevice=if(IsNetworkDevice=1 AND IsLegitimateVendor=0 AND (match(DeviceId, "USB") OR match(HardwareIds, "USB")), 1, 0)
| eval SuspicionScore=(IsKnownPentestVID * 3) + IsSuspiciousHID + IsUSBNetDevice
| where SuspicionScore > 0
| eval RiskReason=case(
IsKnownPentestVID=1, "Known pentest/attack hardware VID detected",
IsSuspiciousHID=1, "Unknown vendor HID device — possible keystroke injector",
IsUSBNetDevice=1, "Unknown USB network adapter — possible LAN tap",
1=1, "Suspicious device class connection")
| table _time, host, SubjectUserName, SubjectDomain, EventCode, ClassName, ClassId, DeviceId, HardwareIds, IsHIDDevice, IsNetworkDevice, IsKnownPentestVID, SuspicionScore, RiskReason
| sort - SuspicionScore, - _timeDetects suspicious hardware additions using Windows Security Event ID 6416 via Splunk WinEventLog:Security sourcetype. Parses the EventData XML to extract device class, hardware IDs, and connecting user. Evaluates each device connection against known pentest tool Vendor IDs (Hak5, Digispark, Raspberry Pi Pico gadget mode, Arduino) and flags HID/network devices from unrecognized vendors. Applies a suspicion score to prioritize: known pentest VIDs score 3, unknown-vendor HID and USB network adapters score 1 each. Requires Windows Advanced Audit Policy — Detailed Tracking — Audit PNP Activity enabled.
Data Sources
Required Sourcetypes
False Positives & Tuning
- IT administrators and developers connecting legitimate USB development boards (Arduino, Raspberry Pi Pico) whose VIDs overlap with attack tooling
- Employees connecting generic/unbranded USB peripherals not in the approved vendor list
- VMware, Hyper-V, or VirtualBox virtual network adapters triggering USB network device events
- OT/SCADA technicians connecting USB-to-Serial adapters for industrial equipment
- Docking station NICs presenting as new devices on first connection to an unfamiliar dock
Other platforms for T1200
Testing Methodology
Validate this detection against 4 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Install Microsoft Loopback Network Adapter via devcon
Expected signal: Windows Security Event ID 6416: ClassName=Net, ClassId={4d36e972-e325-11ce-bfc1-08002be10318}, DeviceId=ROOT\NET\0001 or similar, HardwareIds=*MSLOOP. Windows System Event IDs 20001 and 20003 in System log for driver installation. Entry in C:\Windows\INF\setupapi.dev.log with timestamp and INF path.
- Test 2Enumerate Connected HID Devices via PowerShell
Expected signal: Sysmon Event ID 1: Process Create with Image=powershell.exe and CommandLine containing 'Get-PnpDevice' and 'HIDClass'. Security Event ID 4688 (if command line auditing enabled). PowerShell ScriptBlock Log Event ID 4104 with the full device enumeration script.
- Test 3Query USB Device Connection History via Registry
Expected signal: Sysmon Event ID 1: Process Create for reg.exe with CommandLine containing 'HKLM\SYSTEM\CurrentControlSet\Enum\USB'. Sysmon Event ID 1 also for findstr.exe. Security Event ID 4688 (if enabled) for both processes. Registry access events may be logged depending on SACL configuration.
- Test 4Simulate Keystroke Injection via PowerShell SendKeys
Expected signal: Sysmon Event ID 1: Process Create for powershell.exe initiated by the calling process, plus any processes spawned by the injected keystrokes. If Sysmon monitors for the parent process chain, keystrokes injected into an Explorer window will show explorer.exe as parent. PowerShell ScriptBlock Log Event ID 4104 for both the outer and any inner PowerShell sessions.
References (9)
- https://attack.mitre.org/techniques/T1200/
- https://securelist.com/darkvishnya/89169/
- https://ossmann.blogspot.com/2011/02/throwing-star-lan-tap.html
- https://arstechnica.com/information-technology/2012/03/the-pwn-plug-is-a-little-white-box-that-can-hack-your-network/
- https://docs.microsoft.com/en-us/windows/security/threat-protection/auditing/event-6416
- https://docs.microsoft.com/en-us/windows/security/threat-protection/auditing/advanced-security-audit-policy-settings
- https://learn.microsoft.com/en-us/windows-hardware/drivers/install/devcon-command-syntax
- https://github.com/hak5/bashbunny-payloads
- https://docs.microsoft.com/en-us/windows/win32/devio/device-management-events
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