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USB Devices

Overview

Section titled “Overview”

ARROW devices support USB passthrough, which lets you hand a physical USB device directly to one of your virtual machines. In practice this is how you get a wireless adapter into your Kali VM for wireless testing, though it works for storage, security keys, and other hardware too.

What You Can Attach

Section titled “What You Can Attach”

The everyday use case is an ALFA wireless card for wireless penetration testing. The following are known to work, along with other adapters that support monitor mode:

  • ALFA AWUS036ACH
  • ALFA AWUS036ACHM
  • ALFA AWUS036ACM

You can also pass through USB storage for moving files or collecting evidence, hardware security keys for authentication, license dongles and other specialized hardware, and USB sensors or testing equipment.

Attaching a USB Device to a VM

Section titled “Attaching a USB Device to a VM”

Before you start, the target VM needs to be created and running, you need ARROW Manager access to the device, and the USB device has to be physically plugged into the ARROW device.

The flow is short: plug the device in, open ARROW Manager, go to the Proxmox tab, find your running VM, and attach the device. Attaching restarts the VM, and once it comes back the device is available inside it.

Step by step:

Step 1: Physically connect the USB device to your ARROW device.

Step 2: Open the ARROW Manager dashboard for that device.

Step 3: Go to the Proxmox tab.

Step 4: Find your running virtual machine.

Step 5: In the USB devices section, connected devices are listed with an Attach button.

Step 6: Click Attach next to the device you want to pass through.

Important Attaching a USB device restarts the virtual machine. Save any work in progress before you do this.

Step 7: Wait for the VM to restart, roughly 30 to 60 seconds.

Confirming It Worked

Section titled “Confirming It Worked”

Once the VM is back, log in over SSH or the NoVNC console and check that the device is there. Run lsusb and look for it in the output. An ALFA wireless card, for example, shows up something like:

Bus 001 Device 003: ID 0bda:8812 Realtek Semiconductor Corp. RTL8812AU 802.11a/b/g/n/ac

For wireless cards, confirm the interface exists with ip link show, or check specifically for wireless interfaces with iwconfig.

Detaching a USB Device

Section titled “Detaching a USB Device”

Detach a device when you are done with it, when you want to move it to a different VM, or when you are getting ready to return the ARROW device. Open ARROW Manager, go to the Proxmox tab, find your VM, locate the attached device, and click Detach.

Note Detaching also restarts the virtual machine.

Once the VM restarts, the device is free for another VM or safe to unplug.

Common Use Cases

Section titled “Common Use Cases”

Wireless Penetration Testing

Section titled “Wireless Penetration Testing”

An attached ALFA card gives your VM the ability to discover nearby networks, capture wireless traffic for analysis, run in monitor mode for passive monitoring, and carry out authorized wireless security testing. A typical run: attach the card to your testing VM, put the interface into monitor mode with airmon-ng start wlan0, then work with tools like airodump-ng and aircrack-ng.

USB Storage

Section titled “USB Storage”

Pass through a USB drive to move large files in and out of your VM, store collected evidence off the VM disk, or back up VM data.

Hardware Authentication

Section titled “Hardware Authentication”

Attach a USB security key when you need hardware-based multi-factor authentication or hardware-backed key storage.

Troubleshooting

Section titled “Troubleshooting”

The device does not appear in ARROW Manager. Make sure it is firmly seated, try a different USB port, and confirm the device itself has power (check its LEDs). Refresh the ARROW Manager dashboard, and restart ARROW Manager if it still does not show.

It attached but lsusb does not list it. Confirm the VM actually restarted after the attach and give it 30 to 60 seconds to fully boot. Check the VM logs for USB errors, and if nothing shows, detach and reattach.

The attach fails with an error. The VM has to be running, not stopped or paused, and the device cannot already be attached to another VM. Also confirm the LUKS encrypted storage is unlocked. If it keeps failing, contact support.

A wireless card will not enter monitor mode. Check that the driver is loaded with lsmod | grep 88XXau, and confirm the interface name with iwconfig, since it may not be wlan0. Kill interfering processes with airmon-ng check kill, and make sure the card actually supports monitor mode, because not all do.

Storage is slow or the device keeps disconnecting. Skip USB hubs and connect directly to the ARROW device, try a different cable, and for storage confirm the filesystem is not corrupted. Heavy CPU load can also disrupt USB passthrough, so keep an eye on system resources.

Best Practices

Section titled “Best Practices”

Attaching restarts the VM, so save your work first and confirm the device is one that works over passthrough before you rely on it. During testing, keep track of which devices are attached to which VMs, since passthrough can occasionally be unstable, and note any special setup for next time. When you are finished, detach devices so others can use them, unmount storage before detaching, and remember to pack the USB devices back with the ARROW device when you return it.

Section titled “Related Documentation”