Reverse Engineering

Introduction The firmware is the embedded software that controls the basic functioning of electronic devices, from routers and IP cameras to smart home appliances and industrial systems. Unlike traditional software, firmware operates directly on hardware, making it a critical target in terms of security, functionality, and privacy. Firmware analysis involves examining this embedded software to understand its internal workings, detect potential vulnerabilities, identify backdoors, and in some cases modify or extract relevant information. This type of analysis is particularly relevant in security audits, forensic investigations, reverse engineering, or exploit development. ...

Introduction️ DMR (Digital Mobile Radio) is a digital radio standard developed by the ETSI (European Telecommunications Standards Institute), designed to replace analog radio systems and offer more efficient communications. It operates in TDMA (Time Division Multiple Access) with two time slots within a 12.5 kHz channel, allowing for simultaneous transmissions on the same frequency. It allows additional services beyond voice transmission, such as data sending, like text messages or location reports of terminals. Around voice, it allows both individual calls similar to mobile phone calls and group calls, where registered terminals can participate.️ ...

Introduction️ Various devices marketed in the market both for acquisition by consumers and for rental by Internet service providers’ clients allow their administration through a web portal. This portal may be limited in features and if more advanced configurations are needed, such as configuring the firewall, with the iptables tool, access via console is necessary. The operating system of routers usually is GNU/Linux.️ The console access is usually blocked to prevent problems with incorrect configurations made by inexperienced users, which makes it necessary, for example, to access the serial port by removing the device casing. In other cases, access to the console is allowed through the SSH (Secure Shell) protocol, but access is limited to a restricted console, with pre-defined commands from the manufacturer. These devices usually have a backdoor that allows deploying a command terminal sh or bash with the introduction of specific commands.️ ...

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.️ ...