Verbatim Store 'n' Go Secure Portable SSD Missing Trust

Advisory ID: SYSS-2022-045
Product: Store ‘n’ Go Secure Portable SSD
Manufacturer: Verbatim
Affected Version(s): #53402 (GDMSLK02 C-INIC3637-V1.1)
Tested Version(s): #53402 (GDMSLK02 C-INIC3637-V1.1)
Vulnerability Type: Missing Immutable Root of Trust in Hardware
(CWE-1326)
Risk Level: Medium
Solution Status: Fixed
Manufacturer Notification: 2022-06-29
Solution Date: -
Public Disclosure: 2022-10-07
CVE Reference: CVE-2022-28383
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 insufficient firmware validation, an attacker can store  
malicious firmware code for the USB-to-SATA bridge controller on the  
external drive, which gets executed.

Vulnerability Details:

When analyzing the external data storage Verbatim Store ‘n’ Go Secure
Portable SSD, Matthias Deeg found out that the validation of the
firmware for the USB-to-SATA bridge controller INIC-3637EN only consists
of a simple CRC-16 check (XMODEM CRC-16).

Thus, an attacker is able to store malicious firmware code for the
INIC-3637EN with a correct checksum on the used SPI flash memory chip
(XT25F01D), which then gets successfully executed by the USB-to-SATA
bridge controller.

For instance, this security vulnerability could be exploited in a
so-called “supply chain attack” when the device is still on its way to
its legitimate user.

An attacker with temporary physical access during the supply could
program a modified firmware on the Verbatim Keypad Secure, which always
uses an attacker-controlled AES key for the data encryption, for
example.

If, later on, the attacker gains access to the used USB drive, he
can simply decrypt all contained user data.

Proof of Concept (PoC):

SySS was able to read and write the SPI flash memory containing the  
firmware of the INIC-3637EN controller (128 KB) using a universal  
programmer.

By analyzing the dumped memory content, SySS found out that the  
INIC-3637EN firmware is stored from the file offset 0x4000 to the file  
offset 0x1BFFB, and that the corresponding XMODEM CRC-16 is stored at  
the file offset 0x1FFFC.

Matthias Deeg developed a simple Python tool for updating the checksum  
of modified firmware images before writing them to the SPI flash memory  
chip.

The following output exemplarily shows updating a modified firmware  
image:

$ python update-firmaware.py firmware_hacked.bin  
Verbatim Store 'n' Go Firmware Updater v0.1 - Matthias Deeg, SySS GmbH   
(c) 2022  
[*] Computed CRC-16 (0x0874) does not match stored CRC-16 (0x5E8C).  
[*] Successfully updated firmware file

Solution:

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

Disclosure Timeline:

2022-06-29: Vulnerability reported to manufacturer  
2022-10-07: Public release of security advisory

References:

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

https://www.verbatim.com.au/products/store-n-go-portable-ssd-with-keypad-access/
[2] SySS Security Advisory SYSS-2022-045

https://www.syss.de/fileadmin/dokumente/Publikationen/Advisories/SYSS-2022-045.txt
[3] 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/Materialien/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