Re: Resurrecting the Securing Debian Manual

Excellent idea Noah, especially Debian *server* security. I'm willing to
help. The Wiki option sounds like the best way to me.
Some points:
- SSH server security
- Firewalls: I think someone mentioned nftables, and that is optimal. But
for people choosing between UFW and firewalld front-end tools, why
firewalld will usually be preferable.
- Monitoring/auditing: top/htop/etc, process termination, AIDE/Lynis/etc
- Minimizing the attack surface
- Modern backup strategies
- Looking at the current manual, user security needs to be updated as well.

Thanks for taking this on. As you say, the current manual has
been out-of-date for a long time and is not easily reviseable.
If you would like additional help, please email or contact me at my Discord
<https://discord.com/invite/mggw8VGzUp> server. I support Debian servers
for several customers and use Debian 12 and sid on the client side. Also, I
wrote an SSH server security manual for a customer; it can be reused for
this purpose.

Dave

On Mon, Jun 9, 2025 at 12:21 PM Noah Meyerhans <[email protected]> wrote:

> Hi all.  The Securing Debian Manual (the harden-doc package) is
> woefully out of date and doesn't provide accurate guidance for
> operating modern software in the current threat landscape.  I'd like
> to begin the task of updating it to reflect current best practice and
> to document current tools and technologies.
>
> Most basically, I wonder if folks think this is a worthy idea.  The
> landscape has changed significantly since harden-doc was first
> written.  Default configurations don't require as much hardening, and
> there are lots more available resources.  Maybe harden-doc has
> stagnated because there's no real need for it?
>
> Assuming we do revive the doc, here are some ideas of what I'd like to
> do with the document.  I'd like to also get feedback, ideas, and
> contributions from others interested in the topic.
>
> 1. More background information on principles such as:
>    a. Threat modeling
>    b. Defense in depth
>    c. Least privilege
> 2. Modern server deployment practices, such as:
>    a. Sandboxing (with systemd, containers, etc)
>    b. Image-based deployments, including cloud
>    c. Update deployment strategies for large fleets
> 3. Data privacy:
>    a. VPNs, wireguard, etc
>    b. Disk encryption
> 4. Workstation best practices, including:
>    a. Ssh key generation and handling
>    b. Basic browser hygine
>    c. Password managers and other password hygine
>
> My inclination is to primarily focus on general principles rather than
> try to document specific settings in specific packages, as in the
> current document's Chapter 5 ("Securing services running on your
> system").  It'll make sense to document some approaches to safe usage of
> the most common software (firefox, openssh, etc), but I don't believe
> that it's feasible to provide useful advice for a meaningful subset of
> Debian packages.
>
> Should we maybe consider maintaining this document on wiki.debian.org,
> rather than being a centrally maintained document? The wiki may scale
> better to multiple contributors, leading to better content and more
> active maintenance.
>
> If you've got ideas for other topics, I'd love to hear them.
>
> noah
>
>