Featured Articles

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

This article will describe how to download an image from a (docker) container registry.

Intro

Remember the good ‘ol days when you could just download software by visiting a website and click “download”?

Even apt and yum repositories were just simple HTTP servers that you could just curl (or wget) from. Using the package manager was, of course, more secure and convenient — but you could always just download packages manually, if you wanted.

But have you ever tried to curl an image from a container registry, such as docker? Well friends, I have tried. And I have the scars to prove it.

It was a remarkably complex process that took me weeks to figure-out. Lucky you, this article will break it down.

Examples

Specifically, we’ll look at how to download files from two OCI registries.

Docker Hub GitHub Packages Terms

First, here’s some terminology used by OCI

OCI – Open Container Initiative blob – A “blob” in the OCI spec just means a file manifest – A “manifest” in the OCI spec means a list of files Prerequisites

This guide was written in 2024, and it uses the following software and versions:

debian 12 (bookworm) curl 7.88.1 OCI
. . . → Read More: Manually Downloading Container Images (Docker, Github Packages)

3TOFU: Verifying Unsigned Releases

Verifying Unsigned Releases with 3TOFU

This article introduces the concept of “3TOFU” — a harm-reduction process when downloading software that cannot be verified cryptographically.

⚠ NOTE: This article is about harm reduction.

It is dangerous to download and run binaries (or code) whose authenticity you cannot verify (using a cryptographic signature from a key stored offline). However, sometimes we cannot avoid it. If you’re going to proceed with running untrusted code, then following the steps outlined in this guide may reduce your risk.

TOFU

TOFU stands for Trust On First Use. It’s a (often abused) concept of downloading a person or org’s signing key and just blindly trusting it (instead of verifying it).

3TOFU

3TOFU is a process where a user downloads something three times at three different locations. If-and-only-if all three downloads are identical, then you trust it.

Why 3TOFU?

The EFF’s Deep Crack proved DES to be insecure and pushed a switch to 3DES.

During the Crypto Wars of the 1990s, it was illegal to export cryptography from the United States. In 1996, after intense public pressure and legal challenges, the government officially permitted export with the 56-bit DES cipher — which was a known-vulnerable cipher.

But there
. . . → Read More: 3TOFU: Verifying Unsigned Releases

Nightmare on Lemmy Street (A Fediverse GDPR Horror Story)

Nightmare on Lemmy "A Fediverse GDPR Horror Story"

This article will describe how lemmy instance admins can purge images from pict-rs (click here if you just want to know how).

This is (also) a horror story about accidentally uploading very sensitive data to Lemmy, and the (surprisingly) difficult task of deleting it.

Intro

tl;dr I (accidentally) uploaded a photo of my State-issued ID to Lemmy, and I couldn’t delete it.

Friends don’t let friends compose jerboa comments in bed before coffee (@theyshane)

A few weeks ago I woke up to my 06:00 AM alarm, snoozed my phone, rubbed my eyes, and started reading /c/worldnews (on Lemmy).

Still half-asleep, I was typing a comment when my thumb accidentally hit the “upload media” button. Up popped a gallery of images. I tried to click the back button, but I missed. I tapped on a photo. The photo that I tapped-on was a KYC selfie image (that I took the previous day for a service that has no business having such PII anyway).

That was all it took — two consecutive mis-taps while half-asleep in bed, and my dumb-ass just inadvertently uploaded a KYC selfie onto the public internet. And thanks to archaic State authentication systems, anyone with
. . . → Read More: Nightmare on Lemmy Street (A Fediverse GDPR Horror Story)

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)

Crowdfunding on Crowd Supply (Review of my experience)

Crowd Supply Review - My experience crowdfunding $18,507 in open-source security hardware

In 2021, I raised $18,507 on CrowdSupply to manufacture and sell the BusKill cable. This article will review my experience working with Crowd Supply.

Introduction

So you have a great idea for a cool product, but you’re not sure how to scrap up the necessary funds to ramp-up production and sell it? If you’re a traditional capitalist then you’d be considering financing your new entrepreneurial venture through loans or venture capital.

But you’re not a capitalist. You want to avoid the fat cats draining equity from your hard labor. Your idea is so cool, why not try your hand at crowdfunding direct from your soon-to-be customers?

Why Crowd Supply?

The first place I looked was Kickstarter. But I did some googling, and I saw so many people complain that they backed a project on kickstarter and never received anything from the creator. In fact, Kickstarter’s own Fulfillment Report says that 9% of all their projects fail to deliver.

And, especially in the computer security department, if anyone with half a brain scans through the projects on kickstarter, even the ones that raise $1 million scream SCAM! Either their promises are unrealistic, they clearly have no idea what they’re talking
. . . → Read More: Crowdfunding on Crowd Supply (Review of my experience)

Detecting (Malicious) Unicode in GitHub PRs

Detecting Malicious Unicode in GitHub Pull Requests

This article will describe how you can utilize GitHub Actions to scan user-contributed PRs for unicode and automatically warn you if such commits contain (potentially invisible & malicious) unicode characters.

Why

Last month Trojan Source was published — which described how malicious unicode characters could make source code appear benign, yet compile to something quite malicious.

Michael Altfield

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

About Michael


. . . → Read More: Detecting (Malicious) Unicode in GitHub PRs

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)

We’re on the Darknet! Visit this site at our tor .onion

Visit this site on our .onion

This website is now accessible on the darknet. And how!

Why

Fun fact: the most popular website on the darknet is facebook. There are hundreds of other popular sites on the darknet, including debian, the CIA, the NYT, the BBC, ProPublica, and–now–michaelaltfield.net.

michaelahgu3sqef5yz3u242nok2uczduq5oxqfkwq646tvjhdnl35id.onion

michaelahgu 3sqef5yz3u2 42nok2uczdu q5oxqfkwq64 6tvjhdnl35i     d.onion

All of these organizations chose to make their websites available over .onion addresses so their website will be accessible from millions of daily tor users without leaving the darknet. 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
. . . → Read More: We’re on the Darknet! Visit this site at our tor .onion

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