Fundamentals of IoT firmware reverse engineering

Infosec Institute - 

The Internet of Things (IoT) is a trendy topic these days, and the number of critical vulnerabilities found in these devices is huge. As these devices are often connected to internal networks, a successful exploration involves a tremendous risk to organizations, with criminals accessing internal networks as the best practices and cybersecurity guidelines are not in place. 

Firmware is the name of the software embedded in IoT devices. This piece of code provides low-level control over device-specific hardware components. Although encryption has been used in the last years to protect devices’ firmware image files, the principles to understand and find weaknesses are the same used in the past.

First, we need to download the firmware files from the official repositories. When this is impossible, understand how the update process is done and impersonate legitimate access to the files. A real and common example is the usage of a customized user-agent by the devices when they need to update the firmware to the latest version. By intercepting the requests, we can get them easily.

The next steps do not have a magic execution order. Depending on the firmware, image protection mechanisms decrypting the file may be necessary or just unzipping and

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