Offensive Security

Introduction️ NXDN (Next Generation Digital Narrowband) is a digital radio standard developed jointly by Icom and Kenwood in Japan. It was designed for voice and data communications in bidirectional radio environments, such as mobile and portable radio communication systems used by organizations like emergency services, companies, and government agencies.️ These communications may be sent without encryption or using DES or AES encryption as specified in the NXDN TS 1-D Version 1.3 specification NXDN TS 1-D Version 1.3. In this case we will focus on Scramble encryption, which is defined as follows.️ ...

Introduction️ Nordic nRF51 is a series of system-on-a-chip (SoC) developed by Nordic Semiconductor. These chips are designed specifically for low power and low energy applications in the field of wireless connectivity. The nRF51 series includes several models, such as the nRF51822 and the nRF51802, among others.️ These chips are widely used in low-power devices, such as wearables, IoT sensors (Internet of Things), health devices, and other devices that require efficient connectivity and minimal energy consumption. In the case that we need to perform a reverse engineering analysis on some of these devices it will be necessary to obtain a copy of the firmware from the chip itself of the device.️ ...

Introduction️ Remote controls by infrared (IR) are electronic devices that use infrared signals to communicate with other electronic devices, such as televisions or air conditioners. The basic operation of an IR remote control is based on the emission of infrared signals from the remote towards an infrared receiver in the device being controlled.️ These signals contain specific codes that are interpreted by the receiving device, causing the corresponding action to be executed, such as turning the device on and off, changing channels, or adjusting volume. The infrared signals generated by the IR LED are modulated, meaning the light intensity is periodically modified according to a specific pattern. This modulation pattern is unique for each button or function on the remote control.️ ...

Introduction️ One of the phases of dynamic analysis of Android applications is the interception of connections made by the application to remote servers. In the case that they use the HTTP protocol can be easily intercepted and manipulated with a proxy server since the protocol does not use encryption. But in the case that it uses the HTTPS protocol we will need to install an SSL certificate from a Certification Authority on our device since the connection will be encrypted with this one. Additionally, some applications use the technique of SSL Pinning, which consists in trusting only certain embedded certificates in the application.️ ...

Introduction️ To perform a security audit of an Android application, it is necessary to create a customized environment, which can be based on a physical device or an emulator. For most cases, an emulator will suffice. In this article we will create a virtual machine for Android in x86_64 architecture, and modify it by installing Magisk, to obtain superuser permissions and install modules, and install some applications.️ Installing the Android Emulator For the Android emulator, we have chosen the official Android IDE, Android Studio, which includes support for Android Virtual Devices (AVD). To install the IDE, simply go to its official website and download the installer by accepting the license terms. During the installation process, when selecting the components to install, we will deselect the option Android Virtual Device, as we will configure it later. In this case, we will install the IDE in our Documents directory.️ ...

Introduction️ Between the capabilities of the device Flipper Zero is the decoding of radio protocols below 1 GHz (Sub-GHz) frequencies. One of the available applications is Weather Station that decodes signals from temperature and humidity sensors. Due to the architecture of the application and the nature of the code project it is possible to add new protocols to the application.️ We will add the TWINS protocol based on ThermoPRO-TX4 and Polaroid based on inFactory-TH. We will also observe how to compile the application.️ ...

Introduction️ In this blog topics related to computer security and general computing will be treated with the experience and knowledge acquired over time. On computer security, specifically offensive, topics related to the preparation of technical articles, creation of tools, resolution of Hack The Box machines, software and hardware hacking, and reverse engineering will be covered.️ Offensive security refers to the process of identifying and exploiting vulnerabilities in computer systems with the aim of improving their security. This involves legal and ethical activities, such as participating in learning platforms like Hack The Box, where these skills can be practiced in safe environments.️