The Making of a Secure Open Source Password Keeper from the - - PowerPoint PPT Presentation

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the making of a secure open source password keeper
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The Making of a Secure Open Source Password Keeper from the - - PowerPoint PPT Presentation

Sep 07, 2023 389 likes •918 views

The Making of a Secure Open Source Password Keeper from the electronics to the high-level software Mathieu Stephan Hello! I am Mathieu Stephan - Embedded systems engineer - Former writer for Hackaday - www.limpkin.fr - Mooltipass

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The Making of a Secure Open Source Password Keeper

… from the electronics to the high-level software

Mathieu Stephan

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Hello!

I am Mathieu Stephan

  • Embedded systems engineer
  • Former writer for Hackaday
  • www.limpkin.fr
  • Mooltipass project founder
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What is the Mooltipass?

  • Secure credential & file storage
  • Native browser integration
  • Recognized as a keyboard
  • Multiple users
  • Cross platform
  • Open software & hardware
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The Internals

USB HID Microcontroller OLED screen Flash memory Clickable wheel Mooltipass Mini

PIN-locked smart card, containing the user’s AES-256 key

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Usage Example

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Usage Example

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Presentation Outline

Here’s how... … this adventure started … 20 people collaborated without meeting each other … we produced two devices from the ground up … we created the Mooltipass security model … the Mooltipass hard-, firm- and software was designed ...and what’s next!

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1.

Starting The Project

Getting contributors and setting up the project infrastructure

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Beginning The Mooltipass Adventure

First call for contributors was in December 2013

  • First article on hackaday.com describing the concept
  • “Developed on Hackaday” but not associated with it
  • Received 30 applications!

Work was assigned based on the applicants’... 1) Preferences 2) Available spare time 3) Area of expertise

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Globally Distributed Contributors

me

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The Ground Rules

  • Implement features as determined by consensus
  • Use GitHub for code versioning and source control
  • Document the produced code (doxygen)
  • Work in a dedicated file or folder
  • Follow the chosen coding convention
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Group Communications

Constraint: people have different availabilities!

  • Separate general and development discussion groups
  • Direct contact via IM service (sparingly)

Challenge: keep the momentum going!

  • Show off contributors’ progress
  • Ensure the community feels involved
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Management Infrastructure

Trello - a free online Kanban board

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Management Infrastructure

Based on the Japanese kanban process

  • Respect the roles, responsibilities and titles
  • Leadership at all levels
  • Document & encourage evolutions
  • Maintain a community atmosphere
  • Obtain & manage ETAs without contributors feeling

pressured

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2.

The Mooltipass Hardware

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Functional Prototype

Hand soldered and shipped to contributors

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Mooltipass - Case Choice

Designs made by the community

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Mooltipass - Final Design

110% funded in Dec. 2014

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Mooltipass Mini

300% funded in Oct. 2016

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Mooltipass Mini - Tests

Testing the adhesive strength

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Mooltipass Mini - Tests

...but some people double checked!

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Mooltipass Mass Production

Chinese assembly lines

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Mooltipass Mass Production

CNC shops

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Mooltipass Mass Production

Video instructions for the assembler

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Mooltipass Mass Production

… and a lengthy quality control document

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3.

The Mooltipass Firmware

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Firmware - AES Encryption

  • Using AVR-Cryptolib, CTR mode
  • Checked against NESSIE vector sets
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Firmware - Encrypted Storage

  • Dedicated flash memory used for storage
  • 2 types of data
  • Credentials
  • Encrypted blobs
  • Sorted linked list data structure
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Firmware - Data Structure

Service A Service B ... Login 1 Login 2 Login 3 Login 4

Encryption key stored inside the smart card

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Firmware - Smartcard Use

  • Ubiquitous form of read-protected memory
  • 16-bit PIN access (“0000” to “FFFF”)
  • Permanently locked after 4 incorrect PINs
  • Cheap (<$1) in volume
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Firmware - RNG

  • Uses watchdog timer’s natural jitter
  • Generate 8 bytes per second (!)
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Firmware - USB

  • USB composite: HID keyboard and ‘proprietary’
  • Proprietary channel for integration plugins
  • Keyboard channel for manual password recall
  • USB Keyboards are natively supported by all OSes...
  • ...but LUTs needed for different locales
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Firmware - LUT Generation Tool

… basically bruteforcing a given layout

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Firmware - Graphics Library

  • Designed from the ground up
  • Optimized for speed
  • Features:
  • RLE compression for bitmaps
  • Bitmaps, fonts stored inside the external flash
  • Python scripts to generate the graphics bundle
  • Can be securely updated
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Firmware - Update File Format

graphics bundle (bitmaps, fonts, strings…) padding new firmware version number AES key update flag new firmware padding (new AES key, encrypted) CBC MAC

Fixed size to mitigate CBC MAC weakness

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Firmware - Bootloader

  • Checks signed firmware updates
  • Stored on the device:
  • One unique AES key for firmware signing
  • One unique AES key for hash generation
  • Read-protected UID for device non-tamper check
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Firmware - Security Model

Relies on the fact that :

  • Physical tampering with the device leaves traces
  • Microcontroller programming first requires chip erase

Firmware integrity is therefore checked by:

  • Reading the read-protected UID at device reception
  • Reading user card-dependent hashes
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Firmware - Static Analyses

  • Performed by security groups, researchers...
  • We had access to some of them...
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Flashing the Firmware

Custom-made programming jig

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4.

The Mooltipass Software

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Python Tool - MooltiPy

Created by one contributor:

  • Can use all Mooltipass features
  • Can be called from other apps
  • Pure command line interface
  • Store / recall small files
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Chrome App & Extension

  • Cross-platform
  • Unfortunately Chrome-only
  • Two-click installation:
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Chrome App - MooltiApp

...converted into a standalone App using Electron

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Cross Platform Tool - Moolticute

Daemon Mooltipass HW

Chrome Safari Firefox SSH agent

Moolticute App Moolticute CLI

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Cross Platform Tool - Moolticute

Qt & C++ - Created by a contributor

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Cross Platform Tool - Moolticute

… and now being developed by the Mooltipass team

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4.

The Next Mooltipass Device!

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Next Generation Mini

“Unsafe” MCU U S B ATBTLC1000 Secure MCU OLED Data Flash DB Flash UART LIS2HH12TR SMARTCARD

Secure Domain

May be disabled

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Contributors Wanted!

Firmware:

  • New database model implementation
  • Unicode support implementation
  • Bootloader implementation
  • User interface design
  • U2F implementation
  • < your idea[s] here >
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Contributors Wanted!

  • C++ & QT: frontend for the new firmware features
  • Web: implement a user space on mooltipass.com
  • Python: security implementation checks
  • GIMP: create Mooltipass graphics
  • Android & iOS: App development
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Thanks!

Questions?

You can find me at: limpkin on freenode.net mathieu@themooltipass.com