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Hacking on Willem's Blog

CAPTCHA Alternative

Protect your forms in a user friendly way

July 30, 2022
If you're looking for a user-friendly alternative for CAPTCHA's you should check this post out where I outline how I protect web forms against malicious actors and spammers.

Chances are that you've encountered a CAPTCHA in the wild: they protect web forms by asking you to type over weirdly rendered characters or by asking you to select photos containing a particular thing. Why are they used and is there a user friendly alternative?

Working with special hardware from China

On developing software without a manual

Dec. 31, 2020
This month I reversed engineered my way into developing software for a Chinese Android device with an embedded printer!

This month I received a shipment from China containing some special hardware, Android devices with embedded printers! To make life easier for the restaurant and business owners that use my food ordering app, I want these devices to automatically print new orders. If only I can get these machines to work with my software... challenge accepted!

Making my own tablet OS

Installing and modifying Debian GNU/Linux on Surface Go

Mar. 9, 2020
I wondered if I could escape Windows by installing Debian GNU/Linux on a Surface Go, read along to find out how to do this!

For some years now I use a tablet as main computer, I like its versatility. But, most tablets come with a locked down operating system, like iPadOS, Windows 10S or Android. As I like things my own (weird) way, I wondered if I could escape these "software jails" by installing a free operating system on a tablet. It's possible, read along to find out how I escaped!

Visiting an international hackers conference

OWASP Global AppSec Amsterdam

Sep. 27, 2019
This month I attended Global AppSec Amsterdam, an international conference for hackers and security specialists. Read along for some of the highlights.

This month I was lucky enough to attend Global AppSec Amsterdam, an international conference for hackers and security specialists. There were presentations from former intelligence agents, bounty hunters, academics and software vendors. I learned about some of the newest hacking techniques, met with interesting people and played some cool retro games. Read along for more.

Search like a pro: Google search operators

Comprehensive list of advanced search operators

Apr. 25, 2019
Read along for a comprehensive list of advanced Google search operators that allow you to filter your search results.

You probably use the world's most famous search engine to find things everyday, but you might not know about some of its advanced search operators. You can use these special search phrases to find things that are otherwise burried in the search results. Read along for a comprehensive list of advanced Google search operators.

WordPress: 10 tips to secure your website

Keep hackers out of the world's most popular content management system

Mar. 31, 2019
A lot of people use WordPress to manage their website. Prevent your site from being hacked using this blog post.

A lot of people use WordPress to manage their website, therefore it's no surprise people ask me to have a look at their site's security. As ethical hacker, I encounter WordPress in different shapes, sizes and states. Some of them are really badly protected against hacks. Prevent your site from being hacked using these 10 practical tips.

Understanding the security concerns in shared hosting

Considering open ports and unused network facing services

Feb. 28, 2019
People pay me to hack them, provided I'll explain how I did it. Read along to learn how hackers use security holes to hack your app, webshop or website!

People pay me to hack them, provided I'll explain how it was done, so future hacks can be prevented. As security consultant, I scan for weaknesses in my clients' apps, webshops and websites. Very often a hack starts by exploiting a security hole that is visible remotely. Read along to learn how hackers find security holes and what you can do to secure them.

Rescuing files from a broken harddisk

Make backups to be safe rather than sorry!

Oct. 16, 2018
Yesterday I helped a young woman with her broken computer containing precious photos, could I safe them?

Yesterday a young woman brought me her laptop, it didn't start anymore and it only showed an error message. It turned out to be a broken harddisk. It startled her when I told her that all data on the disk was lost. She told me it contained precious photos of her pregnancy and young child. What could I do?

Helping people with free software

Installing Debian GNU/Linux on an old laptop

July 20, 2018
This week I helped a man with repairing and reinstalling his computer with Debian GNU/Linux.

This week a man brought his laptop to the community centre where I help people with computer problems as volunteer. The old laptop wouldn't start anymore and had to be reinstalled. Instead of Windows, I installed a free operating system. I think it is important to tell you how and why I did it.

Removing paint from a bike frame

Uncover the aluminium with chemicals and sanding paper

June 9, 2018
Using dichloromethane and sanding paper I removed the paint from my bike frame to create a minimal, raw aluminium look.

There is beauty in raw, unfinished material that is often hidden with superfluous layers of paint. I like things to be true to the nature of the material. My bike was painted black - not bad - but I wondered what it really looked like from a material point of view.

Creating a minimal iPhone stand

Routing oak wood for a custom fit

June 2, 2018
Today I created a minimal iPhone stand from oak wood. I used a single piece of wood to get it done.

Today I created a minimal iPhone stand from oak wood. While it's much faster to buy one online, I wanted one to fit my phone horizontally, with its case on. I like minimal design, so I opted to machine a single piece of wood to get it done.

Off the grid: Working on 100% renewable energy

Collecting, storing and using solar electricity to power my phone, computer and wearables

Apr. 30, 2018
Learning from powering my personal devices using nothing but self generated electricity using a solar panel and power banks.

For the past 10 days I have powered my personal electronic devices (phone, computer, wearables) using nothing but energy collected using a small solar panel. I disconnected all grid-connected chargers. I hoped that by going off the grid, even in such a small way, I would gain insights that enable me to save energy (and money).

Cyber security: 5 easy tips to protect your server against hackers

Server hardening best practices for Windows and Linux

Mar. 10, 2018
These 5 practical cyber security measures will improve the safety of server, website and data.

This week one of my clients was hacked and asked me for emergency assistance to help secure their server infrastructure. It was a web server that ran WordPress websites on Apache (with PHP/MySQL), including a few webshops with customer data. This hack could easily have been prevented with the following best practices, is your server secure?

From tree to table

Designing and creating a night stand

Oct. 23, 2017
Creating a night stand from a raw slab of chestnut wood.

Right next to the house were I was born there was this chestnut tree, sadly it died one and a half year ago. When it was taken down, my brother saved me a slab of wood. I intended to create something from it, a nice "do it yourself" adventure, worthy of a blog post!

Saving a MacBook Air with exploded battery

Don’t try this at home - but I did

Sep. 14, 2017
Saving a MacBook Air with a swollen battery pack.

Last night I had a nasty surprise: my original MacBook Air was swollen due to an exploded battery. I immediately had to take action, for reasons of safety and to preserve this piece of modern computer history. Don’t try this at home, but if you do... read along for some practical tips.

Clouds below my floor

Building a little datacenter in my basement

Aug. 31, 2017
Building a little datacenter in my basement utilising a very fast internet connection.

At my home I have this crazy fast optical internet connection. It is a 600MB up and down fibre connection which directly arrives in my home (no copper cables involved). It's like a private internet highway. Reason enough to find out if I could do something to make better use of all this speedy fiber galore...

The day I killed my LAN

Turned off my local network and went 4G only

July 31, 2017
I killed my office LAN and went 4G only. Saves a lot of clutter, energy and money.

Today I called my provider to quit my office's ADSL internet subscription, I don't need it anymore. I have turned off my local area network and switched my workflow onto mobile internet only. The simplicity and savings actually surprised me so much, that I made blog post for it.

Repairing a Nintendo Gameboy Advance SP

Chip surgery to play classic Zelda

Mar. 26, 2017
Reparing an old Nintendo Gameboy Advance to play classic Zelda again.

This month Nintendo released the Switch with Zelda "Breath of the Wild". The new console received positive reviews. The new Zelda game is amazing and can be played on-the-go, thanks to the portability of the Nintendo Switch. But it its hardly the first Nintendo device that features the mythical kingdom of Hyrule with Link and princess Zelda. I found an old Gameboy Advance, perfect for playing classic Zelda games... but it was in need for repair!

Programming on Apple Watch

Serious about crazy experiments

Feb. 16, 2017
Programming with VIM over SSH on Apple Watch using a bluetooth keyboard

Over the past years I have been no stranger to crazy experiments, but this time I really wanted to push it into the extreme: programming on an Apple Watch. Would it be possible to actually write code on such a tiny device? Why even bother? This post is about the case for crazy experiments, and why you should try too!

Batavus Champion bike from 1978

restoring retro glory with some help from the Internet

Sep. 3, 2016
Restore the retro glory of an old bike from the 70s using the internet.

Almost a year ago I bought an old steel racing bike from 1978. I wanted to figure out if using a bike to commute worked for me. It did! I used it to ride more than 1000KM before I decided to get a modern road bike. Now, almost a year later, I decided to put the powers of the internet into good use: to bring the bike back to its retro glory!

Building the blog... in style!

Developing on a 20-year old computer with 16MB RAM and Windows 98

June 23, 2016
Find out if it is possible to turn a computer from the 90s into a modern development machine.

One must be a bit crazy to come up with the idea to build a blog (as in: actual programming) on an old 486 laptop with just 16MB RAM. I happen to be that crazy: I took my very first laptop from the 90s and decided to find out if it was possible to turn it into a development machine.

All blog posts
Wood nerves nicely visible throught the transparent lacquer
Wood nerves nicely visible throught the transparent lacquer
Flocks of paint falling of my bike frame, uncovering the raw aluminium
Flocks of paint falling of my bike frame, uncovering the raw aluminium
Typical CAPTCHA's you may encounter on the web (image credit: Wikipedia and Google)
Typical CAPTCHA's you may encounter on the web (image credit: Wikipedia and Google)
Boot device not found - that's not good
Boot device not found - that's not good
Reading an article on my tablet in portrait mode
Reading an article on my tablet in portrait mode
The stand is very stable
The stand is very stable
Check the reputation of a WordPress plugin by looking at the number of downloads and its rating
Check the reputation of a WordPress plugin by looking at the number of downloads and its rating
An original advertisment of the bike from the 70s - with specification of original parts
An original advertisment of the bike from the 70s - with specification of original parts
A lease on life: the faulty harddisk connected to my laptop
A lease on life: the faulty harddisk connected to my laptop
Leaking personal user information from the WordPress REST API
Leaking personal user information from the WordPress REST API
Defective harddisk
Defective harddisk
The original MacBook Air: Groundbreaking due to its thinness and lack of ports
The original MacBook Air: Groundbreaking due to its thinness and lack of ports
Fresh lacquer... again
Fresh lacquer... again
Safety label on the bottle of dichloromethane: danger, danger, danger!
Safety label on the bottle of dichloromethane: danger, danger, danger!
Sitting on some concrete tiles the modified PC is connected to the internet
Sitting on some concrete tiles the modified PC is connected to the internet
Aligning the wood router
Aligning the wood router
The Tesla PowerWall is a large battery pack that can be used to power an entire house
The Tesla PowerWall is a large battery pack that can be used to power an entire house
Keynote presentation by cyberwarfare specialist, Chris Kubecka
Keynote presentation by cyberwarfare specialist, Chris Kubecka

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