Featured Articles

Continuous Documentation: Hosting Read the Docs on GitHub Pages (2/2)
Crowdfunding on Crowd Supply (Review of my experience)
Introducing BusKill: A Kill Cord for your Laptop
Nightmare on Lemmy Street (A Fediverse GDPR Horror Story)
Hardening Guide for phpList
Trusted Boot (Anti-Evil-Maid, Heads, and PureBoot)
WordPress Multisite on the Darknet (Mercator .onion alias)
WordPress Profiling with XHProf (Debugging & Optimizing Speed)
Detecting (Malicious) Unicode in GitHub PRs
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Trusted Boot (Anti-Evil-Maid, Heads, and PureBoot)

Verifying Boot Integrity with Heads, PureBoot

This post will help to provide historical context and demystify what's under the hood of Heads, PureBoot, and other tools to provide Trusted Boot.

I will not be presenting anything new in this article; I merely hope to provide a historical timeline and a curated list of resources.

Intro

The Librem Key cryptographically verifies the system's integrity and flashes red if it's detected tampering

I've always felt bad about two things:

Because I run QubesOS, I usually disable "Secure Boot" on my laptop I travel a lot, and I don't have a good way to verify the integrity of my laptop (eg from an Evil Maid that gains physical access to my computer)

To address this, I have turned to Heads and PureBoot -- a collection of technologies including an open-source firmware/BIOS, TPM, and a USB security key that can cryptographically verify the integrity of the lowest firmware (and up the chain to the OS).

While Purism has written many articles about PureBoot and has some (minimal) documentation, I found they did a lot of hand waving without explaining how the technology works (what the hell is a "BIOS measurement"?). So I spent a great deal of
. . . → Read More: Trusted Boot (Anti-Evil-Maid, Heads, and PureBoot)

WordPress Profiling with XHProf (Debugging & Optimizing Speed)

Debugging & Optimizing Wordpress Speed with XHProf

This guide will show you how to generate and view XHProf reports of your WordPress Site.

This is useful so you can drill-down and see exactly how many microseconds each of your scripts and functions (themes & plugins) are running when generating a page -- slowing down your website visitors' page load speed.

Michael Altfield

Hi, I’m Michael Altfield. I write articles about opsec, privacy, and devops ➡

About Michael


. . . → Read More: WordPress Profiling with XHProf (Debugging & Optimizing Speed)

Monitoring Tor .onion Websites (uptime alerts)

Uptime Monitoring of Tor .onion Websites

This article will present a few simple website availability monitoring solutions for tor onion services.

Problem

So you've just setup an Onion Service for your website, but how often do you actually check that it's working? Maybe it's a .onion alias to an existing website, and you usually only check it on the clearnet. What's to prevent the darknet presence of your website from going down for weeks without you noticing?

Indeed, it's important to monitor your .onion websites so that you can discover and fix issues before your customers do. But how? Most of the popular uptime monitoring solutions (pingdom, freshping, statuscake, etc) certainly can't monitor .onion websites.

This guide will enumerate some solutions for monitoring .onion websites, so you get an email alert if your site goes down.

Michael Altfield

Hi, I’m Michael Altfield. I write articles about opsec, privacy, and devops ➡

About Michael


. . . → Read More: Monitoring Tor .onion Websites (uptime alerts)

WordPress Multisite on the Darknet (Mercator .onion alias)

How to use a .onion with Wordpress Multisite

This article will describe how to point a .onion domain at your existing wordpress sites (on wordpress multisite) so that your website will be accessible both on the clearnet and directly on the darknet via a .onion domain.

Intro

There are numerous security benefits for why millions of people use tor every day. Besides the obvious privacy benefits for journalists, activists, cancer patients, etc -- Tor has a fundamentally different approach to encryption (read: it's more secure).

Instead of using the untrustworthy X.509 PKI model, all connections to a v3 .onion address is made to a single pinned certificate that is directly correlated to the domain itself (the domain is just a hash of the public key + some metadata).

Moreover, some of the most secure operating systems send all the user's Internet traffic through the Tor network -- for the ultimate data security & privacy of its users.

In short, your users are much safer communicating to your site using a .onion domain than its clearnet domain.

For all these reasons, I wanted to make all my wordpress sites directly available to tor users. Unfortunately, I found that it's not especially easy to point a .onion domain at
. . . → Read More: WordPress Multisite on the Darknet (Mercator .onion alias)

Hardening Guide for phpList

phpList Hardening Guide Featured Image

This post will outline recommended steps to harden phpList after install to make it reasonably secure.

phpList is the most popular open-source software for managing mailing lists. Like wordpress, they have a phplist.com for paid hosting services and phplist.org for free self-hosting.

Earlier this week, it was announced that phpList had a critical security vulnerability permitting an attacker to bypass authentication and login as an administrator using an incorrect & carefully-crafted password in some cases. This bug is a result of the fact that [a] PHP is a loosely typed language and [b] the phpList team was using the '==' operator to test for equality of the user's hashed password against the DB. This security pitfall has been known in PHP since at least 2010 (a decade ago!), but I'm sure the same mistake will be made again..

Indeed, security is porous. There's no such thing as 100% vulnerability-free code, and phpList is no exception. But if we're careful in adding layers of security to our infrastructure, then we might be able to protect ourselves from certain 0-days.

That said, here's my recommended steps to making your phpList install reasonably secure.

Michael Altfield

Hi, I’m Michael Altfield. I write articles
. . . → Read More: Hardening Guide for phpList

Introducing BusKill: A Kill Cord for your Laptop

Bus Kill: A USB Kill Cord for your Laptop

This post will introduce a simple udev rule and ~$20 in USB hardware that effectively implements a kill cord Dead Man Switch to trigger your machine to self-destruct in the event that you're kicked out of the helm position.

Rubber Ducky I <3 you; you make hack time lots of fun!

Let's consider a scenario: You're at a public location (let's say a cafe) while necessarily authenticated into some super important service (let's say online banking). But what if--after you've carefully authenticated--someone snatch-and-runs with your laptop?

Maybe you can call your bank to freeze your accounts before they've done significant financial harm. Maybe you can't.

Or maybe your laptop was connected to your work VPN. In less than 60 seconds and with the help of a rubber ducky, the thief could literally cause millions of dollars in damages to your organization.

Surely there must be some solution to trigger your computer to lock, shutdown, or self-destruct when it's physically separated from you! There is: I call it BusKill.

Michael Altfield

Hi, I’m Michael Altfield. I write articles about opsec, privacy, and devops ➡

About Michael


. . . → Read More: Introducing BusKill: A Kill Cord for your Laptop

Mitigating Poisoned PGP Certificates (CVE-2019-13050)

Cert Flooding Featured Image

This article will describe PGP Certificate Flooding attacks as well as inform the reader

How to detect if you have a poisoned certificate in your keyring, How to identify & clean the poisoned cert, and How to update the configuration to prevent it from importing poisoned certs in the future

Last month, an attacker spammed several high-profile PGP certificates with tens of thousands (or hundreds of thousands) of signatures (CVE-2019-13050) and uploaded these signatures to the SKS keyservers.

Without looking very deep, I quickly stumbled on 4 keys that were attacked last month:

Michael Altfield

Hi, I’m Michael Altfield. I write articles about opsec, privacy, and devops ➡

About Michael


. . . → Read More: Mitigating Poisoned PGP Certificates (CVE-2019-13050)

Ephemeral Firefox with Extensions (2/3)

icon of ephemeral firefox with icons of popular extensions below it

I recently posted about how to create a sandboxed firefox profile to compartmentalize (and shred) your firefox browsing history in an Ephemeral Firefox session. But so far I've only covered how to create a simple vanilla firefox profile. What if you want your Ephemeral Firefox to include a few basic extensions?

This post will cover how to add extensions to your Ephemeral Firefox profile.

Part 1/3: Ephemeral Firefox in Ubuntu Part 2/3: Ephemeral Firefox with Extensions Part 3/3: Ephemeral Firefox as a Site-Specific Browser Michael Altfield

Hi, I’m Michael Altfield. I write articles about opsec, privacy, and devops ➡

About Michael


. . . → Read More: Ephemeral Firefox with Extensions (2/3)

Ephemeral Firefox in Ubuntu (1/3)

ephemeral firefox

This post will describe how to create an Ephemeral Firefox session. The ultimate goal of an Ephemeral Firefox session is to unlink your browsing sessions day-to-day and reduce tracking via fingerprinting.

Part 1/3: Ephemeral Firefox in Ubuntu Part 2/3: Ephemeral Firefox with Extensions Part 3/3: Ephemeral Firefox as a Site-Specific Browser

This technique can also be used to compartmentalize your internet activity by using the Ephemeral Firefox session as a Site Specific Browser. This can be especially useful for websites that are infamous for tracking users across the internet and selling the data they collect. For example, you can blacklist all facebook domains in your main browser and only use Ephemeral Firefox sessions that have been whitelisted exclusively for facebook domains--effectively compartmentalizing your facebook activity from the rest of your internet activity.

Another great use-case for an Ephemeral Firefox is for public access computers such as those at libraries, hotels, and printing shops.

Michael Altfield

Hi, I’m Michael Altfield. I write articles about opsec, privacy, and devops ➡

About Michael


. . . → Read More: Ephemeral Firefox in Ubuntu (1/3)