Breaking Secure Boot on Google Nest Hub (2nd Gen) to run Ubuntu

Posted on Wed 15 June 2022 in Article • Tagged with arm, amlogic, bootloader, exploit, nest, secureboot, uboot, ubuntu, usb

In this post, we attack the Nest Hub (2nd Gen), an always-connected smart home display from Google, in order to boot a custom OS.

First, we explore both hardware and software attack surface in search of security vulnerabilities that could permit arbitrary code execution on the device.

Then, using a …

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Booting Ubuntu on Google Chromecast With Google TV

Posted on Mon 29 November 2021 in Article • Tagged with arm, amlogic, bootloader, bootrom, chromecast, uboot, ubuntu, usb

In a previous post, we detailed a vulnerability in the Amlogic System-On-Chip bootROM that allows arbitrary code execution at EL3. Since the Chromecast with Google TV (CCwGTV) is one of the devices affected by this issue, it opens the possibility to run a custom OS like Ubuntu.

This post describes …

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Dump Amlogic S905D3 BootROM from Khadas VIM3L board

Posted on Tue 09 February 2021 in Article • Tagged with arm, amlogic, bootloader, bootrom, khadas, vim3l

This post describes how to dump bootROM from Amlogic S905D3 SoC using Khadas VIM3L board. Since this board doesn't use Secure Boot, we can execute custom code in Secure World (a.k.a TrustZone) without exploiting any vulnerability. In addition, the board exposes an UART connector, which is convenient for …

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Reverse engineer USB stack of Exynos BootROM

Posted on Tue 16 June 2020 in Article • Tagged with arm, exynos, samsung, bootrom, usb, reverse, ghidra

In the previous post, we explained how to dump Exynos bootROM.

Exynos (8895 in this post) bootROM contains a minimal USB stack to load a signed bootloader from an USB host (a.k.a. boot from USB). This post summarizes how this USB stack can be reversed using the Great …

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Emulating Exynos 4210 BootROM in QEMU

Posted on Wed 07 March 2018 in Article • Tagged with arm, exynos, samsung, bootrom, qemu, emulation, bootloader, secureboot

QEMU has support for the SMDKC210 machine, an ARM board based on Exynos 4210 SoC. Peripherals implemented in QEMU for this machine are UART, SDHCI, FIMD, I2C, Interrupt Combiner, GIC, Clock, PMU, RNG, MCT, PWM, RTC.

Samsung Galaxy S2 phone is also based on Exynos 4210, so it should be …

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Netgear Nighthawk R7800 : add USB camera support to create a security webcam

Posted on Wed 22 November 2017 in Article • Tagged with kernel, netgear, usb, v4l2

This article explains how to customize Nighthawk X4S firmware to add a security camera feature to this always-online & almost-always-idle device. Alternative firmwares like OpenWRT or LEDE exist, but they don't fully support all stock features yet. So instead this approach is based on modified stock firmware.

Netgear Nighthawk X4S Serious webcam

Main steps are:

  • Customize …

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Amlogic S905 SoC: bypassing the (not so) Secure Boot to dump the BootROM

Posted on Wed 05 October 2016 in Article • Tagged with vulnerability, amlogic, arm, security, firmware, trustzone, bootrom, bug

The Amlogic S905 System-On-Chip is an ARM processor designed for video applications. It's widely used in Android/Kodi media boxes. The SoC implements the TrustZone security extensions to run a Trusted Execution Environment (TEE) that enables DRM & other security features :

S905 block diagram
Amlogic S905 System Block Diagram

The SoC contains a Secure …

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PowerLine (PLC) support in OpenWrt for D-Link DHP-1565

Posted on Sat 20 February 2016 in Article • Tagged with PLC, dhp-1565, AR7400, openwrt

D-Link 1565 is one of the few routers which integrates a PLC (Power line Communication) chipset (in this case QCA AR7400). Unfortunately, OpenWrt does not provide support for this feature yet.

This post presents configuration steps to enable PLC support in OpenWrt for this device.

Hardware configuration

By digging into …

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Analysis of Nexus 5 Monitor mode

Posted on Thu 25 December 2014 in Article • Tagged with arm, security, qualcomm, firmware, android, nexus, trustzone

This article will first describe how to locate the Monitor mode code in Nexus 5 firmware (hammerhead-ktu84p-factory-35ea0277, bootloader-hammerhead-hhz11k : c32f8bec310c659c1296739b00c6a8ac). Then, we will try to understand what it does (its functionalities). Finally, you will have to find bugs by yourself because I didn't find far !

Note: Terms (Non-)Secure …

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Exploitation of Philips Smart TV

Posted on Thu 13 November 2014 in Article • Tagged with mips, smarttv, libupnp, philips, exploit

This post is a translated summary of the article published for my talk at SSTIC 2014 conference (french).

My Philips Smart TV is a Linux box standing there in my living room : that's a sufficient reason to try to get root.

Debug serial port

Internet hackers have already discovered a …

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