Recent content on Sawyer Shepherd's Blog
Heads up: This post is targeting the most popular programmer, the CH341A/B Black model. There are two versions of this model floating around. The most common, older version has capacitor C4 on the opposite side of the crystal oscillator, and the other, newer version has the capacitor C4 on the same side as the crystal oscillator. I am using the newer version to demonstrate this fix. It should work…
TL;DR Use +1 (555) 123-4567 ext. 890. It’s immediately identifiable as a phone number and encodes semantic information in its format, including the area code, exchange code, and line number. Introduction Good UX should minimize cognitive load on the user. It seems phone number formats missed that memo–I read and type a lot of phone numbers for my job, and I can say that nearly all…
I’ve found there’s no better way for blue teamers to gain active defense experience than to do “live fire” exercises against a red team. I’m usually pretty hard on the blue teamers in these exercises. They are given admin credentials to a network of vulnerable boxes they’ve usually never seen before. In 30 minutes, they have to document the systems, backup…
Introduction NixOS offers great declarative system configuration, but by design, every output is stored in the world-readable /nix/ directory. Sooner or later, you’ll find that you need to configure an option with secrets that you don’t want world-readable, let alone in a public Git repository! Agenix solves this issue by encrypting secrets with host SSH keys via the Age application…
Shocker is a retired easy Linux box by mrb3n. It was released on October 3rd, 2017. Scanning I began by scanning the machine: $ nmap -A -T4 10.10.10.56 Starting Nmap 7.93 ( https://nmap.org ) at 2023-09-30 21:59 EDT Nmap scan report for 10.10.10.56 Host is up (0.031s latency). Not shown: 998 closed tcp ports (conn-refused) PORT STATE SERVICE VERSION 80/tcp open http Apache httpd 2.4.18 ((Ubuntu))…
Delivery is a retired easy Linux box by ippsec, available on Hack The Box. It was released on January 9th, 2021. Scanning I began by scanning the machine: $ nmap 10.10.10.222 -p- -O ... PORT STATE SERVICE 22/tcp open ssh 80/tcp open http 8065/tcp open unknown ...unknown-linux-gnu... Let’s run a more intensive scan on the open ports: $ nmap -p 22,80,8065 -sV -sC -T4 PORT STATE SERVICE VERSION…
In case you didn’t notice, my website has been offline for a good while—since Christmas 2022, I believe. Additionally, it now looks like this… While it used to look like this… I’ve migrated from building my site with my own custom static site generator Sawsge and hosting it on my own server to building it with Hugo and hosting it on Github pages. I’m surprised…
Note that BTRFS swapfiles across multiple devices (pools, RAIDs) are not supported1. BTRFS on Linux kernels before version 5.0 can result in filesystem corruption2. From the Arch Wiki: Btrfs on Linux kernel before version 5.0 does not support swap files. Failure to heed this warning may result in file system corruption. While a swap file may be used on Btrfs when mounted through a loop device,…
After recently purchasing my first 3D printer, I have developed some thoughts on the technology in general. I’ve had friends in the 3D printing scene preach the virtues of the technology for years now. Still, I was unconvinced. It seemed like quite an expensive investment for the infrequent payoff of being able to print something useful. After all, I could always fall back on my friends who…
Soldering is an indispensable skill for countless fields of interest, from electric luthierie to car repair. While I am not a master at soldering, I hope by sharing what I have learned I may help beginners struggling to solder clean joints. Safety Soldering can be a dangerous activity. There are high temperatures and toxic fumes involved, but with proper precautions, most health risks can be…
Written by environmentalist Aldo Leopold, A Sand County Almanac is one of the most elegant pieces of nature writing I have ever read. While only formally educated in forestry, Leopold displays a mastery of language in his stunning descriptions of outwardly simple experiences. The novel is well-known in conservation circles for pioneering the idea of land ethic—the concept that the natural…
I have released my program Can on RubyGems and the Arch User Repository. Introduction I have a feeling this post is going to get hairy with a program name like Can! Can is an idea for a program I’ve had for a very long time. As the FreeDesktop.org trash specification says, “An ability to recover accidentally deleted files has become the de facto standard for today’s desktop user…
I have remodeled my entire server stack to better defend against critical vulnerabilities. I know this blogpost is long overdue, with the waves Log4Shell sent through the security world having mostly passed, but I promise my action was timely! Background Previously, my server ran Debian 11 (Bullseye) with a custom sandboxing SystemD configuration for every service I ran (read more about my old…
I placed third at the end of the challenge, winning myself $50. This is how I solved the hardest and least-solved questions of each category. Introduction I’ve been trying to work on my resume recently, and what better way to do it than with a fun CTF organized by a local college? The competition ran from 10 A.M. to 3:30 P.M. on Sunday, November 13th. There were 33 applicants (including…
My server used to be an old gaming desktop, now running Debian 11. I publish my blog with a custom static site generator written in Ruby. Hardware This website is running off an old midrange gaming computer, from circa 12 years ago. I received it for free from a friend, who himself also got it for free from an elderly neighbor. The specs are as follows: MSI K9N6PGM2-V2 Motherboard AMD Athalon II…
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