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Mobile Phones: Should you be afraid of disclosing your IMSI ?

The smartphone has become so important in daily life that users should be concerned about its security. We try to explain here some reasons to be or not to be afraid about disclosing the IMSI, the subscriber identity number used in the global telecommunication network.

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Create (and automatically correct) multiple choice tests with AMC

AMC, for Auto Multiple Choice, is software that allows a teacher to create multiple-choice tests in a very simple way. But, the most interesting part of AMC, is the ability to automatically correct the tests of all students!

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Cyrange : firewall configuration

The cyrange Cyber Range is composed of multiple docker containers. After installation, here is how to configure your firewall to allow communication between the different components...

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Cloning a disk with CloneZilla

Cloning the old disk or installing the new one from zero? That question crossed many minds and this post might help you finding the answer by explaining how to clone your old disk to a new one using CloneZilla and some disk management tools.

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Configure Apache reverse proxy in front of cyrange

In a previous blog post, we showed how to install cyrange cyber range web interface using docker-compose. So now the cyrange Docker container is exposed on port 8080 on your server, and the guacamole container is exposed on port 8081. In this blog post we show how to configure Apache as a reverse proxy in front of your containers.

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Laravel optimization : self-hosted fonts

By default, Laravel (and Bootstrap) applications use fonts (like Nunito or Raleway) that are provided and hosted by Google. This is easy to use for developers, but comes with some drawbacks, including a performance penalty. Luckily, there is an open source project that makes it simple to use self-hosted fonts: fontsource.org

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Deploy Loki on Kubernetes, and monitor the logs of your pods

Loki is a log database developed by Grafana Labs. In a previous blog post we have shown how to run Loki with docker-compose. In this blog post we will deploy Loki on a Kubernetes cluster, and we will use it to monitor the log of our pods.

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Cyber Security Challenge 2022

Cyber Security Challenge 2022 will start in March 2022! It's time to register...

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Getting started with Helm

Helm is a template engine that can be used to deploy applications on a Kubernetes cluster. It allows to build a customized kubernetes resources definition, that can be deployed on your cluster. But helm has actually many other functionalities, to handle the whole process of building, distributing, installing and managing Kubernetes applications.

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A bit of PIL for bit plane display

Displaying image bit planes, in particular less significant ones, is an important task to reveal some image artefacts due to image degradation or manipulation. In particular, the Least Significant Bit (LSB) of pixel values is heavily used in steganography to hide messages in a cover image. We will see in this blog how to use the Python Imaging Library (PIL) to save and display an image containing some specified bit planes of a given image.

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Apache : log real IP addresses behind a reverse proxy

It's quite common now to run your web application behind a reverse proxy or a loadbalancer. This is typically the case if you are running your application in a Kubernetes cluster. In this case, the IP address that is logged by Apache is the IP of the proxy server, which is quite misleading and useless. To get Apache to log the real IP address of the clients, you will have to enable and configure the module remoteip.

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Laravel optimization : reduce CSS size

CSS files are a render blocking resource: the browser waits for your CSS files to be downloaded before rendering the page. This means that, as long as the browser is downloading CSS, the user is waiting in front of a black page...

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