APL's Demoscene

APL is one of the most curious programming languages you’ll ever run across. For example, take a random problem out of Rosetta Code: “Numbers divisible by their individual digits, but not by the product of their digits.”. Here’s a typical implementation in C: #include <stdio.h> int divisible(int n) { int p = 1; int c, d; for (c=n; c; c /= 10) { d = c % 10; if (!d || n % d) return 0; p *= d; } return n % p; } int main() { int n, c=0; for (n=1; n<1000; n++) { if (divisible(n)) { printf("%5d", n); if (!

Exploring Teams' Json Transcript

I was recently interested in doing some data analysis of a Microsoft Teams transcript - specifically to understand if I was talking too much and not giving other folks the opportunity to speak. If you’ve ever wondered something similar (or wanted to do data analysis for other reasons), you might have seen the option to download meeting transcripts. The default options are docx files (Word documents) and VTT files: The VTT files are handy, but turning that data format into something you can process requires writing a mini little parser.

Security Risks of Postman

Postman is an extremely popular application for developers testing remote web APIs. It lets you craft HTTP requests, interact with their responses, and go through the history of what you’ve sent and received. Many of these HTTP requests are authenticated, meaning that the application deals with API keys, login tokens, credentials, etc. In May, Postman pivoted to be a cloud-only product for many of its features. Postman’s Security Risk When you log in to Postman, it automatically syncs all data to their cloud service – including sensitive data contained in these requests.

leeholm16 in LNK file forensic artifacts

Once in a while, I’ll stumble on a question online (or get an email) from a person wondering “Who the heck is leeholm16?” If you’re reading this post, you’re likely one of them :) I never know exactly what situation leads people to ask the question, but they’ve invariably started using a forensic parsing tool against Windows PowerShell.lnk or Windows PowerShell (x86).lnk. For example, here is the forensic analysis of the LNK file included in a SANS408 course.

Installing PowerShell on Steam Deck

If you’re looking to play with the cool Desktop Mode on your shiny new Steam Deck, you might have already seen that it is Arch Linux under the hood. Time to get your favourite shell on there :) Here’s how to get PowerShell running using the community-contributed PowerShell binaries in the Arch User Repository! ## Create a password for root passwd ## Allow pacman to write to the filesystem, and initialize ## pacman with its trusted keys sudo steamos-readonly disable sudo pacman-key --init sudo pacman-key --populate archlinux sudo pacman -Syy ## Clone powershell-bin from the Arch User Repository git clone https://aur.

Watchy is the Arduino Project You've Been Looking For

Watchy is an exciting Open Source E-Paper Watch, based on Arduino and the ESP32 micro controller. I’ve been a fortunate early backer, and doubly fortunate to have been part of some of the early waves that already have their physical Watchy. The component shortage has impacted the whole industry, and SQFMI is no different. However, the great news is that supply has opened up and SQFMI is currently in the process of shipping another huge wave of orders with more to come next month.

Precision Computing Turns 20!

20 years ago, I decided to put up a “Web Log” - or “blog” for short :) I didn’t know what would become of it, but I’m happy that I started. In the years since, this site has seen a ton of change: Hosted on a FreeBSD server under my desk, blogging via Perl and Bash scripts Once I started working on Encarta (which used an XML-based pipeline), ported to XML and XSL stylesheets, with a build system to generate HTML Once C# and .

Powershell Cookbook 4th Edition Now Available!

I am extremely excited to announce that the 4th edition of the PowerShell Cookbook is now available! Now in its 4th edition, the PowerShell Cookbook is now available from Amazon and other major retailers. The 1st edition of the PowerShell Cookbook came out in 2007 - nearly 14 years ago! It had the single goal of making you immediately effective with PowerShell. While the Cookbook of course dives deep into all PowerShell’s most important cmdlets and language features, it teaches you in the context of accomplishing real-world tasks.

Powershell Pocket Reference 3rd Edition Now Available!

It’s alive! Now in its 3rd edition, the PowerShell Pocket Reference is now available from Amazon and other major retailers. The Pocket Reference series, excerpted from the references of the PowerShell Cookbook, puts concise summaries of all of the information you need about PowerShell on a day-to-day basis right at your fingertips. Want to refresh your memory about how to write a zero-width negative lookbehind assertion in a PowerShell regular expression?

Data Exfiltration via Mouse Wiggles

A class of security research out there that is a never-ending source of entertainment is “novel” communication methods. This shows up in many ways in the security industry, including: “Novel” C2 communication channels (DropBox, Telegram, DNS, Instagram comments, …) “Novel” air gap jumping techniques (HDD lights, high-frequency audio, …) “Novel” sideband communication techniques (Steganography, communication via processor cache latency) Ultimately, computers are amazing at encoding data and communicating in various ways, and humans are amazing at inventing various ways.