Switching a Xiaomi Mi Mix 2s to LinageOS (Android 9)

Recently I upgraded from my “old” Motorola/Lenovo G6 plus to a Xiaomi Mi Mix 2s. Why the new phone? Main reasons for that upgrade were: The old phone started to look like a banana. Seriously, I carry my phone in my back pockets and after a year that.. let to a more-than-slightly bent phone. This might have let to another problem: random vibra-call activation. Originally I thought that I was just imagining them, but recently my phone started to vibrate while it was in my hand — while no notification or interaction at all was happening.

Building an LTE Access point with OpenWRT Rooter

My LTE internet connection (70 Mbit downstream, 15 MBit upstream) came with a combined Huawei B315s LTE modem/access point. As I was using it for the last two to three years a couple of problems did arise: the internet connection was often shaky, oftentimes the uplink connection got lost and I had to power-cycle the modem/access point. Subjectively this got improved with the last system upgrade. while the internet down speed on the wired connection was good, the speed achieved through the wireless connection was atrocious (see measurements later in this blog post) the power supply is badly built and takes the space of two power outlets.

To Fuzz a WebSocket

During a recent assignment the customer server was utilizing a WebSocket for some notification transport, part of my assignment was to fuzz-test the used WebSocket (and the messages transported over it). To do this, I turned to my typical tools: PortSwigger BURP only supports display of WebSocket messages but not altering and/or automated fuzzing of websocket messages. OWASP ZAP can inject and fuzz web sockets (e. g. using FuzzDB vectors), alas the tested application disconnects the websocket and thus prevents ZAP from performing the fuzzing attack.

JWT: Signature-vs-MAC attacks

During a recent pen-test I stumbled upon a JSON Web Token(in short: JWT) based authorization scheme. JWTs consist of three parts: header, payload and verification information. The initial header part contains the name of the algorithm that will later be used to generate the verification part of the JWT. This is dangerous as an attacker can change this information and thus (maybe) control what scheme will be used for verification by the server.

On Reframing

There’s power in switching mental models. In my work, switching from “there might be a vulnerability in this software” to “i just haven’t found the vulnerability” was a game changer for me. I get nervous prior to presentations; one switch that helped me was that instead of thinking “my goal is to look bright” I try to remember that my goal is to teach the audience something and it doesn’t matter who stupid I look as long as they gain something from me.

Amazing (Physical) Access Control with HID RFID cards

So my company moved to a new building which uses HID RFID cards for access control. These cards are typically white with some sort of numeric code printed on one side of them. I have not included an image of my card due to (later) obvious reasons.. Setting up my Proxmark3 RDV4 reader Some time ago I joined the Kickstarter for an updated version of the Proxmark3 RFID reader/writer and immediately broke it during the initial flash update.

This year's review, 2018 edition

This year was good work- and health-wise, but bad when it comes to money and relationships. Financially the stock market drop hurt, emotionally getting dumped was painful. For 2019, I plan to keep and improve my healthy 2018 habits: enjoy life as non-smoker, keep on bouldering (6a+ - 6c with a rare sent 7a in-between), finally finish a full Bikram yoga sequence and maybe meditate more often. In addition, I’d like to improve my sleep.

Wireguard vs OpenVPN on a local Gigabit Network

Wireguard is recently making a splash as human-configurable low-overhead alternative to OpenVPN and IPSec. As some privacy-centric VPN providers are planning to support it (e.g., PIA) or already have a beta running (e.g., IVPN, as tested by Ars Technica) it was time for me to look into it. The Setup To get a better feeling about the used technology I directly connected my laptop to my desktop (gigabit Ethernet with no switch/router in between) and setup OpenVPN with a minimalist configuration as well as with a more realistic TLS-configuration.

Revising my lazy http/https interception setup

I’ve wrote about about creating a simple wireless (WLAN for us right-pondian) http/https interception setup before. Mostly I’m using this as a first step when testing mobile/desktop applications. Linux’ network-manager is perfectly able to create an software access-point with most modern network cards. Alas GNOME’s configuration tool only allows for the creation of ad-hoc networks (and switching to KDE for just this is a bit overkill for me) so you have to setup the access point on the command line with nmtui or nmcli.

Living with changes

This year seems to bring a lot of changes: I’ve switched employers after staying on/off at a research center or the last twelve years. When I started there, I was doing cool network coding for the SECOQC quantum key distribution network, it somehow felt as being a part of some bigger undertaking that finally let to something. My work had a tenable outcome, this compensated for the long hours and poor pay.