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Creating a custom operating system similar to EncroChat’s

Writer's picture: Jedi OldenburgerJedi Oldenburger

Creating a custom operating system similar to EncroChat’s for secure communication on a Linux base is not only feasible but has specific advantages due to Linux’s flexibility and security features.



In detail how to make a Linux-Based Custom OS - The Guide:


Advantages of a Linux-Based Custom OS:

1. Open Source:

• Linux is open source, making it highly customizable for security-focused features.

2. Flexibility:

• Ability to remove unnecessary components, reducing the attack surface.

3. Security Features:

• Built-in support for features like SELinux (Security-Enhanced Linux) and AppArmor.

• Advanced encryption tools (e.g., LUKS for full-disk encryption).

4. Wide Hardware Support:

• Linux can be deployed on a range of hardware, from embedded systems to desktops.

5. Community Support:

• A vast community and ecosystem of tools for secure communication and OS hardening.

6. Reduced Vendor Lock-In:

• Independence from major corporations like Google or Apple.

7. Auditability:

• Open codebase allows thorough security audits.


Disadvantages of a Linux-Based Custom OS:

1. User Experience:

• Linux systems can be more challenging to make user-friendly for non-technical users.

2. Device Compatibility:

• Some modern hardware lacks full Linux driver support.

3. Development Complexity:

• Requires expertise in Linux kernel development, device driver management, and secure system design.

4. Support and Maintenance:

• Custom Linux OS requires ongoing updates and patches to stay secure.


Key Features for a Secure Linux OS:

1. Full-Disk Encryption:

• Use LUKS or similar tools to encrypt all data on the device.

2. End-to-End Encrypted Communication:

• Integrate messaging protocols like Signal Protocol or Matrix for secure communication.

3. Tamper-Resistant Mechanisms:

• Implement secure boot with cryptographic verification.

• Self-destruct mechanisms for sensitive data.

4. Minimalist Design:

• Only include necessary services and applications.

• Disable unused peripherals (e.g., cameras, microphones, GPS).

5. Secure Networking:

• Use VPNs, Tor, or custom relay servers for anonymized communication.

6. Panic Features:

• Allow users to wipe the device with a specific PIN or trigger.




linux security custom os

Creating a custom operating system similar to EncroChat’s (Android OS) in Linux.


1. Start with a Lightweight Base Distribution:

• Use minimal distributions like:

Alpine Linux: Lightweight and security-focused.

Arch Linux: Highly customizable.

Debian Minimal Install: Stable and widely supported.


2. Harden the Kernel:

• Apply patches like Grsecurity or use Hardened Linux kernels.

• Configure SELinux or AppArmor for enhanced security.


3. Enforce Encryption:

• Full-Disk Encryption: Implement LUKS or dm-crypt.

• File-Level Encryption: Use GPG or similar tools.


4. Develop Secure Communication Tools:

• Use open protocols like Signal for messaging.

• Build or integrate apps for secure calls (e.g., ZRTP for VoIP encryption).


5. Implement a Custom UI:

• Use lightweight window managers (e.g., i3, Openbox) or build a custom graphical interface for usability.


6. Networking Anonymity:

• Preconfigure Tor or I2P for all network traffic.

• Disable standard DNS in favor of DNS over HTTPS (DoH) or DNS over TLS (DoT).


7. Device Security:

• Remove or disable unused hardware features.

• Use tamper-evident hardware modifications.


8. Audit and Penetration Testing:

• Conduct regular security audits.

• Simulate attacks to identify vulnerabilities.


Potential Use Cases:

Secure Corporate Communication: A Linux-based OS for business teams handling sensitive information.

Privacy-Focused Individuals: Tech-savvy users seeking full control over their data.

Government and NGOs: Secure platforms for high-stakes communication in politically sensitive environments.


Technologies and Tools to Explore:

Operating System Customization:

• Yocto Project: Build custom Linux distributions.

• Buildroot: Minimal OS customization.

Security Tools:

• SELinux, AppArmor, LUKS, GPG.

Messaging Protocols:

• Signal Protocol, Matrix, OpenPGP.

Networking:

• Tor, WireGuard, OpenVPN.

Development Environment:

• QEMU and VirtualBox for testing.


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Here’s a comprehensive step-by-step guide for creating a secure Linux-based operating system with examples for secure messaging, OS customization, and encryption setup. The process includes practical coding and configuration where applicable.


1. Setting Up a Minimal Linux Distribution


Step 1: Choose a Base OS


Use a lightweight Linux distribution:

Alpine Linux: Security-focused and minimal.

Debian Minimal: Stable and customizable.


Install Alpine Linux


Download the ISO from Alpine’s website, and follow the installation guide:


setup-alpine


During installation:

• Set up a strong root password.

• Use encrypted LVM for storage.


2. OS Hardening


Step 2.1: Harden the Linux Kernel


Install a hardened kernel like Grsecurity or enable SELinux/AppArmor.


Enable SELinux


sudo apt install selinux-basics selinux-policy-default auditd

sudo selinux-activate

sudo reboot


Enable AppArmor (Alternative)


sudo apt install apparmor

sudo systemctl enable apparmor

sudo reboot


Step 2.2: Minimize Attack Surface

• Remove unnecessary packages and services:


sudo apt purge <unnecessary-package>

sudo systemctl disable <unnecessary-service>


• Limit root access by configuring sudoers:


sudo visudo


Add:


<username> ALL=(ALL) ALL


3. Full-Disk Encryption Setup


Step 3.1: LUKS Full-Disk Encryption

1. Install LUKS:


sudo apt install cryptsetup


2. Encrypt Disk:


sudo cryptsetup luksFormat /dev/sdX


3. Open Encrypted Partition:


sudo cryptsetup open /dev/sdX encrypted_drive


4. Format and Mount:


sudo mkfs.ext4 /dev/mapper/encrypted_drive

sudo mount /dev/mapper/encrypted_drive /mnt


4. Secure Messaging


Step 4.1: Setting Up a Secure Messaging Protocol


Use the Signal Protocol for secure communication.


Install Matrix Synapse Server


Matrix is an open-source, encrypted communication protocol.


sudo apt install matrix-synapse

sudo systemctl start matrix-synapse


Configure /etc/matrix-synapse/homeserver.yaml for security:

• Enable TLS (HTTPS).

• Set a strong admin password.


Step 4.2: Build a Simple Secure Messaging Client


Python example using matrix-nio:


from nio import AsyncClient, LoginResponse

import asyncio


async def main():

    client = AsyncClient("https://your-matrix-server.com", "@your-username:your-server.com")

    response = await client.login("your_password")

    

    if isinstance(response, LoginResponse):

        print("Logged in successfully!")

        await client.room_send(

            room_id="!your-room-id:your-server.com",

            message_type="m.text",

            content={"msgtype": "m.text", "body": "Hello, secure world!"}

        )

    await client.close()


asyncio.run(main())


5. Secure Networking


Step 5.1: Force All Traffic Through Tor

1. Install Tor:


sudo apt install tor


2. Configure Tor for transparent proxying:

Edit /etc/tor/torrc:


TransPort 9040

DNSPort 5353


3. Route all traffic through Tor:


sudo iptables -t nat -A OUTPUT -p tcp --dport 80 -j REDIRECT --to-ports 9040

sudo iptables -t nat -A OUTPUT -p tcp --dport 443 -j REDIRECT --to-ports 9040


6. Panic Features


Step 6.1: Self-Destruct Script for Data Wipe


Create a script to wipe sensitive data:


#!/bin/bash

# Wipe sensitive directories

rm -rf /home/user/documents/*

shred -u /home/user/.ssh/*

echo "All sensitive data wiped!"


Make it executable and map it to a “panic PIN”:


chmod +x /usr/local/bin/self_destruct


Trigger with a specific keybinding using xdotool or xbindkeys.


7. Testing and Deployment


Step 7.1: Test in a Virtual Environment


Use QEMU or VirtualBox to test your OS.


QEMU Example:


qemu-system-x86_64 -hda my_os_image.qcow2 -m 2048 -enable-kvm


Step 7.2: Deploy to Hardware


Use tools like Etcher or dd to flash your OS to hardware:


sudo dd if=my_os_image.iso of=/dev/sdX bs=4M


8. Maintenance and Updates

• Automate updates using cron:


sudo apt update && sudo apt upgrade -y


• Regularly audit security settings using tools like Lynis:


sudo apt install lynis

sudo lynis audit system


Conclusion


This system provides robust security through full-disk encryption, hardened OS configuration, and secure communication. For further improvement, consider:

• Adding custom kernel patches.

• Incorporating advanced monitoring tools.

• Using tamper-evident hardware.


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