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During a recent security assignment I came upon a projects folder stored on a Microsoft Active Directory server and accessible thought the network (SMB/CIFS). It had the commonly used layout of a single subdirectory per project, users should only be able to access their corresponding projects and this is configured through ACLs. Initial tests did indicate that the access rights were given away sloppily as I was able to access some of those subdirectories. ...

So a customer of mine thought about ordering a Red Team Assessment and wanted me to go through their local network beforehands — no need to make it too easy for the red teamers. The customer’s network was a typical windows network, dated but kept up to date by two admins. Microsoft Defender was rolled out at all clients, and on some servers. A laptop with Kali Linux was connected to the local network, this was my starting point. ...

So I’ve been using a Raspberry Pi 4b+ together with a WaveShare LTE Modem as 4G router/access-point for my home network setup. I do like my hardware to be quiet and thus fan-less, alas the Raspberry Pi 4b+ gets a tad on the warm side. So this was a perfect opportunitiy to play around with an older Raspberry Pi 3b+ which should use approx. 20-25% less power (both, during idle and load) and with “new” software. ...

AppSec includes all tasks that (hopefully) introduce a secure software development life cycle to development teams. Its final goal is to improve security practices and, through that, to find, fix and preferably prevent security issues within applications. It encompasses the whole application life cycle from requirements analysis, design, implementation, verification as well as maintenance. To contrast AppSec with a traditional penetration-test: the latter tries to find vulnerabilities within an already existing application while AppSec focuses upon preventing vulnerabilities from entering the application code in the first place. Penetration Tests are also part of AppSec but they are used rather late in the project runtime to verify the security quality of the application and as input for how the development process can be augmented to prevent similar vulnerabilities from subsequently entering the application. ...

Recently I had a couple of customers that needed some guidance about secure software development. I assume that this happens because I am a developer gone pen-tester so I’ve seen both side of the “problem”. Of course, suggestions differ between software stacks and the overall customer professionalism level, but there is a common starting ground that should be suitable for any professional software project. Without those, anything more advanced would be built upon shaky grounds. Please note, that those are just the starting ground and should not be a limiting set for further improvements. ...

During a recent presentation on HTTP Header Security I was asked for a “simple” flow chart with directions which headers can be used without too many problems. The result was this: What was the reasoning? Initially, basic headers that unify browser behavior are set. They control behavior that is already set when using modern browsers (e.g., Referrer-Policy) or unify non-standard behavior (e.g, X-Content-Type-Options: nosniff). The basic idea behind those headers is, that web developers need to make sure that their website works with those anyway (otherwise people using modern browsers might complain) so it makes sense to take care of those situations during development. ...

Given that I’ve spent more time in my flat (hello, COVID-19) I also spent more time looking at my book shelf.. and wasn’t too happy with it: in hindsight, some of the books I’ve read are way to pretentious and the books I remember as life-changing were mostly read on my kindle anyways. Speaking of Kindles, my first kindle (must be bought around 2008 in the United States) was stored between the books.. with a quite bulging lithium ion battery.. good thing I did that cleanup. ...

So I am back at teaching web application security. This time I wanted to setup a CTF challenge for my students. To not reinvent the wheel, or rather, to stand on the shoulders of giants I am reusing the OWASP Juice Shop vulnerable web app in its CTF mode. Normally I would teach at a (physical) lab which would make the setup easy: all students are situated in the same physical room, I can setup the game server on my laptop and distribute virtual machines containing the vulnerable web app over the local network. Well, that thing called COVID-19 happened so this is not an option right now. ...

After I’ve bought a new and fast 1TB SSD, it’s time to setup my aging Desktop again. Last time I went with Fedora Core, this time I will try to reduce some of the ubuntu-iness of a Ubuntu 20.10 Desktop for that. After preliminary tests Ubuntu seems to be more resource efficient than Fedora Silverblue and I should be able to remove most of Ubuntu’s problematic packages. Given that my Notebook still runs Fedora Core, I’m also keeping in touch with both the Ubuntu/Debian as well as with the Redhat/Fedora world through that. ...

Now that wireguard will be part of the upcoming Linux 5.6 Kernel it’s time to see how to best integrate it with my Raspberry Pi based LTE-Router/Access Point Setup. What is my scenario? Raspberry Pi 3 with a LTE hat, using a public IP address. This will be the VPN server (called edgewalker in this post) An Android Phone that should use the VPN for all communication when connected An Linux Laptop that should use the VPN only accessing network services that are exposed to the VPN Each device connected to the VPN should be able to connect to all other devices, e.g., my phone should be able to connect to a webserver running on the laptop as long as both are part of the VPN network. If setup is easy enough I’m actually thinking about adding my (Ethernet-connected) Desktop to the VPN too. ...