full-disclosure - [FD] [SYSS-2025-016]: Verbatim Store 'n' Go Secure Portable SSD (security update v1.0.0.6) - Offline brute-force attack

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Message-ID: <946997df-3465-46a0-9ec9-d43aa585bb8b@syss.de>
Date: Mon, 20 Oct 2025 12:06:18 +0200
From: Matthias Deeg via Fulldisclosure <fulldisclosure@...lists.org>
To: <fulldisclosure@...lists.org>
Subject: [FD] [SYSS-2025-016]: Verbatim Store 'n' Go Secure Portable SSD
 (security update v1.0.0.6) - Offline brute-force attack

Advisory ID:               SYSS-2025-016
Product:                   Store 'n' Go Secure Portable SSD
Manufacturer:              Verbatim
Affected Version(s):       Part Number #53402 (GDMSLK02 C-INIC3637-V1.1)
Tested Version(s):         Part Number #53402 (GDMSLK02 C-INIC3637-V1.1)
Vulnerability Type:        Use of a Cryptographic Primitive with a Risky
                            Implementation (CWE-1240)
Risk Level:                High
Solution Status:           Open
Manufacturer Notification: 2025-02-21
Solution Date:             -
Public Disclosure:         2025-10-20
CVE Reference:             Not assigned yet
Author of Advisory:        Matthias Deeg, SySS GmbH

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Overview:

The Verbatim Store 'n' Go Secure Portable SSD is a portable USB drive
with AES 256-bit hardware encryption and a built-in keypad for passcode
entry.

The manufacturer describes the product as follows:

"The AES 256-bit Hardware Encryption seamlessly encrypts all data on the
drive in real-time with a built-in keypad for password input. The hard
drive does not store passwords in the computer or system's volatile
memory making it far more secure than software encryption. Also, if it
falls into the wrong hands, the hard drive will lock and require
re-formatting after 20 failed password attempts."[1]

Due to an insecure design, the Verbatim Store 'n' Go Secure Portable SSD
with the latest security update[2] is vulnerable to an offline brute-force
attack for finding out the correct passcode and the corresponding data
encryption key, thus gaining unauthorized access to the stored encrypted
data.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Vulnerability Details:

When analyzing the external storage device Verbatim Store 'n' Go Secure
Portable SSD with the latest security update[2], Matthias Deeg found
out that it is still possible to perform offline brute-force attacks
against this device because of an insecure design.

Compared to the brute-force attack published in 2022 regarding an older
firmware version (see SySS Security Advisory SYSS-2022-043[3]), the
Verbatim Store 'n' Go Secure Portable SSD with the latest firmware
version uses a different AES encryption mode, AES-XTS instead of
AES-ECB, and the logic for verifying the entered passcode was changed.

Nevertheless, an attacker can still gain access to all required data
for performing an offline brute-force attack.

The device consists of the following four main parts:

1. An SSD with M.2 form factor
2. A USB-to-SATA bridge controller (INIC-3637EN)
3. An SPI flash memory chip (XT25F01D) containing the firmware of the
    INIC-3637EN
4. A keypad controller (unknown chip, marked "SW611 2201")

For encrypting the data stored on the SSD, the hardware AES engine of
the INIC-3637EN is used. The firmware version of the latest security
update uses AES-XTS-256 (XEX-based tweaked-codebook mode with ciphertext
stealing[4]). This mode of operation requires a 512-bit XTS key and
so-called 128-bit tweaks for decrypting different disk sectors.

The cryptographic key for the actual data encryption, the so-called data
encryption key (DEK), is stored in a special sector of the SSD which in
turn is encrypted using a so-called key encryption key (KEK).

This KEK is derived from the entered passcode which can be between five
and twelve digits long, and can be generated by the keypad controller.

When the unlock button is pressed on the Verbatim Store 'n' Go Secure
Portable SSD, the first half of the generated AES-XTS key (32 bytes) is
transmitted via SPI communication from the keypad controller to the
USB-to-SATA bridge controller INIC-3637EN for configuring the
corresponding hardware AES engine together with a static second half of
the AES-XTS key (32 bytes).

For verifying the entered passcode, the firmware of the INIC-3637EN
reads and decrypts the special sector on the SSD with the provided KEK,
and it checks specific data offsets for known byte patterns.

If this check is successful, the entered passcode and its derived
AES-XTS key are considered correct, enabling the firmware access to
the decrypted DEK, which can then be used to decrypt the actual user
data.

This described design of the Verbatim Store 'n' Go Secure Portable SSD
allows for offline brute-force attacks for finding the correct passcode
and the corresponding DEK. An attacker can generate the derived AES-XTS
keys (KEK) for all possible passcodes and then try to correctly decrypt
the data of the specific SSD sector. If the resulting plaintext meets
certain criteria, the correct passcode and data encryption key was
found, which then allows for gaining unauthorized access to the
encrypted user data.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Proof of Concept (PoC):

For demonstrating the offline brute-force attack, Matthias Deeg
developed a brute-forcing software tool which checks the complete
search space of all possible passcodes between five and twelve digits.

The following output exemplarily shows a successful attack:

# ./vks-cracker 8 /dev/sda
  █████   █████ █████   ████  █████████       █████████ 
              █████
░░███   ░░███ ░░███   ███░  ███░░░░░███     ███░░░░░███ 
            ░░███
  ░███    ░███  ░███  ███   ░███    ░░░     ███     ░░░  ████████ 
██████    ██████  ░███ █████  ██████  ████████
  ░███    ░███  ░███████    ░░█████████    ░███         ░░███░░███ 
░░░░░███  ███░░███ ░███░░███  ███░░███░░███░░███
  ░░███   ███   ░███░░███    ░░░░░░░░███   ░███          ░███ ░░░ 
███████ ░███ ░░░  ░██████░  ░███████  ░███ ░░░
   ░░░█████░    ░███ ░░███   ███    ░███   ░░███     ███ ░███ 
███░░███ ░███  ███ ░███░░███ ░███░░░   ░███
     ░░███      █████ ░░████░░█████████     ░░█████████  █████ 
░░████████░░██████  ████ █████░░██████  █████
      ░░░      ░░░░░   ░░░░  ░░░░░░░░░       ░░░░░░░░░  ░░░░░ 
░░░░░░░░  ░░░░░░  ░░░░ ░░░░░  ░░░░░░  ░░░░░
  ... finds out your passcode.

Verbatim Keypad Secure Cracker v0.8 by Matthias Deeg 
<matthias.deeg@...s.de> (c) 2022,2025
- - ---
[*] Initialize passcode hash table
[*] Found 16 CPU cores
[*] Reading magic sector from device /dev/sda
[*] Initialize passcode hash table
[*] Start cracking ...
[+] Success!
     The passcode is: 13372025
     The DEK is: 
a715e0b4523eb8fd3651b291bd7bb976a6ebeff3c5a0ebacdf3cf41a8ef1bb82f244b6809e86b5cecab0bb109b2c9119da78f8d49725ae479e479f6c3320b139
[*] Have a nice day.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Solution:

SySS GmbH is not aware of a solution for the described security issue.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Disclosure Timeline:

2025-02-21: Vulnerability reported to manufacturer
2025-03-10: Vulnerability reported to manufacturer again
2025-10-20: Public release of security advisory

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

References:

[1] Product website for Verbatim Store 'n' Go Secure Portable SSD

https://www.verbatim-europe.com/en/external-ssd/products/store-n-go-portable-ssd-with-keypad-access-256gb-53402
[2] Verbatim Store 'n' Go Portable SSD Security Update 1.0.0.6

https://www.verbatim-europe.com/files/products/store-n-go-secure-portable-ssd-with-keypad-access/keypad-products-update-1006-manual.zip
[3] SySS Security Advisory SYSS-2022-043

https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2022-043.txt
[4] Wikipedia: Disk encryption theory - XTS
     https://en.wikipedia.org/wiki/Disk_encryption_theory#XTS
[5] SySS Security Advisory SYSS-2025-016

https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2025-016.txt
[6] SySS GmbH, SySS Responsible Disclosure Policy
     https://www.syss.de/en/responsible-disclosure-policy

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Credits:

This security vulnerability was found by Matthias Deeg of SySS GmbH.

E-Mail: matthias.deeg (at) syss.de
Public Key: 
https://www.syss.de/fileadmin/dokumente/PGPKeys/Matthias_Deeg.asc
Key fingerprint = D1F0 A035 F06C E675 CDB9 0514 D9A4 BF6A 34AD 4DAB

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Disclaimer:

The information provided in this security advisory is provided "as is"
and without warranty of any kind. Details of this security advisory may
be updated in order to provide as accurate information as possible. The
latest version of this security advisory is available on the SySS
website.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Copyright:

Creative Commons - Attribution (by) - Version 3.0
URL: http://creativecommons.org/licenses/by/3.0/deed.en

Download attachment "OpenPGP_signature.asc" of type "application/pgp-signature" (841 bytes)

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