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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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 any...so far !

Note: Terms (Non-)Secure …


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[QPSIIR-80] Qualcomm TrustZone Integer Signedness bug

Posted on Thu 18 December 2014 in Advisory • Tagged with vulnerability, advisory, arm, security, qualcomm, android, trustzone

Summary

Qualcomm TrustZone is prone to an integer signedness bug that may allow to write NULL words to barely controllable locations in memory.

The vulnerability can be triggered from Non-Secure World through the TrustZone call "tzbsp_smmu_fault_regs_dump".

This issue has been discovered in Samsung Galaxy S5 firmware, but other devices can …

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