This repository contains Linux hardening guidance, example commands, and example scripts for Debian and Ubuntu systems.

It is not a managed security product, and it is not intended to be treated as a drop-in guarantee of safety.

This repository is primarily scoped to:

• Debian
• Ubuntu
• Debian- and Ubuntu-like systems using:
  • APT
  • systemd
  • UFW
  • AppArmor

The guidance and scripts are written for:

• workstations
• administrative endpoints
• small self-managed servers

They are not guaranteed to apply cleanly to:

• RHEL
• Fedora
• CentOS Stream
• Arch
• Alpine
• OpenSUSE
• non-systemd distributions

Please report issues that could cause users to make unsafe changes, including:

• incorrect commands
• unsafe defaults in example scripts
• misleading guidance that could expose services unintentionally
• steps that could lock users out of remote systems without proper warning
• documentation that materially misrepresents Debian or Ubuntu behavior

Please do not use this repository as a channel for:

• general Linux troubleshooting requests
• unsupported distro-specific issues outside the repository scope
• theoretical issues with no practical impact on the commands or workflows here
• requests for private security support

If you believe a command, script, or workflow in this repository could lead to:

• unintended network exposure
• broken authentication
• weakened local hardening
• dangerous persistence or boot behavior

please report it privately first if possible.

Do not publish exploit-style writeups about repository mistakes before giving a reasonable chance to correct them.

Example scripts in this repository are intentionally conservative, but they are still examples.

Users should:

1. read every script before running it
2. test changes on non-production systems first
3. avoid applying remote-access-affecting changes without a rollback path
4. verify all state changes after applying them

This repository is provided as documentation and example code.

You are responsible for:

• testing it
• validating it
• deciding whether it fits your system’s role
• maintaining rollback access