Modify USB Armory DHCP IP Pool

2 minute read

In this post we will modify the default DHCP configuration on the USB Armory so that the DHCP address pool will be between and instead of -

Mounting the SD card

Get the USB Armory SD card and plug it in your computer.

We retrieve the location of the SD card with dmesg.

dmesg | tail
[ 6585.912905] usbcore: registered new interface driver usb-storage
[ 6585.913908] usbcore: registered new interface driver uas
[ 6586.914159] scsi 6:0:0:0: Direct-Access     Generic- SD/MMC/MS PRO    1.00 PQ: 0 ANSI: 4
[ 6586.915257] sd 6:0:0:0: Attached scsi generic sg5 type 0
[ 6587.746850] sd 6:0:0:0: [sde] 62333952 512-byte logical blocks: (31.9 GB/29.7 GiB)
[ 6587.747347] sd 6:0:0:0: [sde] Write Protect is off
[ 6587.747357] sd 6:0:0:0: [sde] Mode Sense: 2f 00 00 00
[ 6587.747853] sd 6:0:0:0: [sde] Write cache: disabled, read cache: enabled, doesn''t support DPO or FUA
[ 6587.750287]  sde: sde1
[ 6587.751805] sd 6:0:0:0: [sde] Attached SCSI removable disk

Here we see that the SD card is located at /dev/sde. We can verify that this is indeed the correct device with fdisk -l /dev/sde (we know that our card size is about 32GB).

sudo fdisk -l /dev/sde
Disk /dev/sde: 29,7 GiB, 31914983424 bytes, 62333952 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x7e2bdd5b

Device     Boot Start     End Sectors  Size Id Type
/dev/sde1       10240 7167999 7157760  3,4G 83 Linux

We create a directory where the SD card will be mounted.

sudo mkdir /mnt/usbarmory

And mount the SD card :

sudo mount /dev/sde1 /mnt/usbarmory

Modifying the IP adressess

We start by modifying the network interface IP addresses. We edit the file with:

vim /mnt/usbarmory/etc/network/interfaces

And we modify it so that it looks like this

# interfaces(5) file used by ifup(8) and ifdown(8)
# Include files from /etc/network/interfaces.d:
source-directory /etc/network/interfaces.d
auto usb0
allow-hotplug usb0
iface usb0 inet static

Then we modify the DHCP server configuration:

vim /mnt/usbarmory/etc/dhcp/dhcpd.conf
# A slightly different configuration for an internal subnet.
subnet netmask {
  default-lease-time 600;
  max-lease-time 7200;

Finally we can unmount our SD card

sudo umount /mnt/usbarmory

Test it

Put back the SD card in the USB Armory, plug it in your computer. You should be automatically connected to a new network. Try connecting to the USB Armory with :

ssh usbarmory@ -o PasswordAuthentication=yes