What is kali linux persistence

What is kali linux persistence

In this workshop, we will examine the various features available to us when booting Kali Linux from USB devices. We will explore features such as persistence, creating LUKS encrypted persistence stores, and even dabble in “LUKS Nuking” our USB drive. The default Kali Linux ISOs (from 1.0.7 onwards) support USB encrypted persistence.

0x01 — Start by imaging the Kali ISO onto your USB drive (ours was /dev/sdb). Once done, you can inspect the USB partition structure using parted /dev/sdb print:

For ease of use, please use a root account. This can be done with “sudo su”.

[email protected]:~$ dd if=kali-linux-2023.2-live-amd64.iso of=/dev/sdb conv=fsync bs=4M 

0x02 — Create and format an additional partition on the USB drive. In our example, we create a persistent partition in the empty space above the Kali Live partitions:

When fdisk completes, the new partition should have been created at /dev/sdb3 ; this can be verified with the command lsblk .

0x03 — Encrypt the partition with LUKS:

[email protected]:~$ cryptsetup --verbose --verify-passphrase luksFormat /dev/sdb3 

0x04 — Open the encrypted partition:

[email protected]:~$ cryptsetup luksOpen /dev/sdb3 my_usb 

0x05 — Create an ext4 filesystem and label it:

[email protected]:~$ mkfs.ext4 -L persistence /dev/mapper/my_usb [email protected]:~$ e2label /dev/mapper/my_usb persistence 

0x06 — Mount the partition and create your persistence.conf so changes persist across reboots:

[email protected]:~$ mkdir -p /mnt/my_usb [email protected]:~$ mount /dev/mapper/my_usb /mnt/my_usb [email protected]:~$ echo "/ union" | sudo tee /mnt/my_usb/persistence.conf [email protected]:~$ umount /dev/mapper/my_usb 

0x07 — Close the encrypted partition:

[email protected]:~$ cryptsetup luksClose /dev/mapper/my_usb 

Now your USB drive is ready to plug in and reboot into Live USB Encrypted Persistence mode.

Multiple Persistence Stores

At this point we should have the following partition structure:

We can add additional persistence stores to the USB drive, both encrypted or not… and choose which persistence store we want to load, at boot time. Let’s create one more additional non-encrypted store. We’ll label and call it “work”.

0x01 — Create an additional, 4th partition which will hold the “work” data. We’ll give it another 5GB of space:

[email protected]:~$ parted /dev/sdb GNU Parted 2.3 Using /dev/sdb Welcome to GNU Parted! Type 'help' to view a list of commands. (parted) print Model: SanDisk SanDisk Ultra (scsi) Disk /dev/sdb: 31.6GB Sector size (logical/physical): 512B/512B Partition Table: msdos Number Start End Size Type File system Flags 1 32.8kB 2988MB 2988MB primary boot, hidden 2 2988MB 3050MB 64.9MB primary fat16 3 3050MB 10.0GB 6947MB primary (parted) mkpart primary 10000 15000 (parted) quit Information: You may need to update /etc/fstab. 

0x02 — Format the fourth partition, label it “work”:

[email protected]:~$ mkfs.ext4 /dev/sdb4 [email protected]:~$ e2label /dev/sdb4 work 

0x03 — Mount this new partition and create a persistence.conf in it:

[email protected]:~$ mkdir -p /mnt/usb [email protected]:~$ mount /dev/sdb4 /mnt/usb [email protected]:~$ echo "/ union" > /mnt/usb/persistence.conf [email protected]:~$ umount /mnt/usb 

Boot the computer, and set it to boot from USB. When the boot menu appears, edit the persistence-label parameter to point to your preferred persistence store!

Emergency Self Destruction of Data in Kali

As penetration testers, we often need to travel with sensitive data stored on our laptops. Of course, we use full disk encryption wherever possible, including our Kali Linux machines, which tend to contain the most sensitive materials. Let’s configure a nuke password as a safety measure:

[email protected]:~$ sudo apt install -y cryptsetup-nuke-password [email protected]:~$ dpkg-reconfigure cryptsetup-nuke-password 

The configured nuke password will be stored in the initrd and will be usable with all encrypted partitions that you can unlock at boot time.

Backup you LUKS keyslots and encrypt them:

[email protected]:~$ cryptsetup luksHeaderBackup --header-backup-file luksheader.back /dev/sdb3 [email protected]:~$ openssl enc -e -aes-256-cbc -in luksheader.back -out luksheader.back.enc 

Now boot into your encrypted store, and give the Nuke password, rather than the real decryption password. This will render any info on the encrypted store useless. Once this is done, verify that the data is indeed inacessible.

Lets restore the data now. We’ll decrypt our backup of the LUKS keyslots, and restore them to the encrypted partition:

[email protected]:~$ openssl enc -d -aes-256-cbc -in luksheader.back.enc -out luksheader.back [email protected]:~$ cryptsetup luksHeaderRestore --header-backup-file luksheader.back /dev/sdb3 

Our slots are now restored. All we have to do is simply reboot and provide our normal LUKS password and the system is back to its original state.

Updated on: 2023-May-30
Author: g0tmi1k

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What is kali linux persistence

Kali Linux “Live” has two options in the default boot menu which enable persistence — the preservation of data on the “Kali Live” USB drive — across reboots of “Kali Live”. This can be an extremely useful enhancement, and enables you to retain documents, collected testing results, configurations, etc., when running Kali Linux “Live” from the USB drive, even across different systems. The persistent data is stored in its own partition on the USB drive, which can also be optionally LUKS-encrypted.

To make use of the USB persistence options at boot time, you’ll need to do some additional setup on your “Kali Linux Live” USB drive; this article will show you how.

This guide assumes that you have already created a Kali Linux “Live” USB drive as described in the doc page for that subject. For the purposes of this article, we’ll assume you’re working on a Linux-based system.

You’ll need to have root privileges to do this procedure, or the ability to escalate your privileges with sudo .

In this example, we assume:

• your USB drive is /dev/sdb (last letter will probably be different). Check the connected usb drives with the command lsblk and modify the device name in the usb variable before running the commands)
• your USB drive has a capacity of at least 8GB — the Kali Linux image takes over 3GB, and for this guide, we’ll be creating a new partition of about 4GB to store our persistent data in

In this example, we’ll create a new partition to store our persistent data into, starting right above the second Kali Live partition, put an ext4 file system onto it, and create a persistence.conf file on the new partition.

1. First, begin by imaging the latest Kali Linux ISO (currently 2023.2) to your USB drive as described in this article. We’re going to assume that the two partitions created by the imaging are /dev/sdb1 and /dev/sdb2 . This can be verified with the command lsblk .
2. Create and format an additional partition on the USB drive. First, let’s create the new partition in the empty space above our Kali Live partitions. We have to do this from the command line as gparted will read the imaged ISO as a large block:

[email protected]:~$ usb=/dev/sdb [email protected]:~$ [email protected]:~$ sudo fdisk $usb  

[email protected]:~$ usb=/dev/sdb [email protected]:~$ [email protected]:~$ sudo mkfs.ext4 -L persistence $3 

[email protected]:~$ usb=/dev/sdb [email protected]:~$ [email protected]:~$ sudo mkdir -p /mnt/my_usb [email protected]:~$ sudo mount $3 /mnt/my_usb [email protected]:~$ echo "/ union" | sudo tee /mnt/my_usb/persistence.conf [email protected]:~$ sudo umount $3