3108, 2022

DeepSec 2022 Talk: Auditing Closed Source Trusted Applications for Qualcomm Secure Execution Environment (QSEE)- Hector Marco & Fernando Vano

Sanna/ August 31, 2022/ Conference

Smartphones have become essential devices for carrying out many daily activities, including security-sensitive tasks such as authentication and payments. The security of sensitive data in modern mobile devices relies on hardware-enabled Trusted Execution Environments, amongst which ARM TrustZone is one of the most widely used. Qualcomm Secure Execution Environment (QSEE) is one of the most widespread commercial TEE solutions in the smartphone space, used by many devices such as Xiaomi, Motorola and several devices of the Google Nexus and Pixel series. In order to audit the QSEE environment, security researchers have to face distinct challenges. On the one hand, the software components of QSEE (i.e., trusted operating system and trusted applications) are not open sourced and can be quite complex, which requires a considerable extent of reverse engineering efforts to conduct analysis and to

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2010, 2021

DeepSec 2021 Talk: Firmware Surgery: Cutting, Patching and Instrumenting Firmware for Debugging the Undebuggable – Henrik Ferdinand Nölscher

Sanna/ October 20, 2021/ Conference

Embedded systems can be challenging to analyze. Especially on automotive systems, many things that we take for granted on other software such as debugging and tracing do not always work. This is further complicated by watchdogs and peripheral processors, that go haywire when strict timing and communication requirements are violated. On some systems, debugging is even impossible because debugging resources such as pins are either used for something else or they don’t exist at all! Assuming that code can be dumped, the solution for this can be emulation, however emulating a rich automotive system can be painful and many times, only few aspects of the system can be sufficiently modeled. What if there was an in-between? How can we debug, fuzz and tamper embedded firmware without access to real-time debugging or emulation? In this

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2211, 2018

ROOTS 2018 Talk: Kernel-Assisted Debugging of Linux Applications – Tobias Holl, Philipp Klocke, Fabian Franzen

Sanna/ November 22, 2018/ Conference, ROOTS

On Linux, most—if not all—debuggers use the ptrace debugging API to control their target processes. However, ptrace proves unsatisfactory for many malware analysis and reverse engineering tasks: So-called split-personality malware often adapts its behavior in the presence of a debugger, yet ptrace makes no attempt to hide from a target process. Furthermore, ptrace enforces a strict one-to-many relation meaning that while each tracer can trace many tracees, each tracee can only be controlled by at most one tracer. Simultaneously, the complex API and signal-based communications provide opportunities for erroneous usage. Previous works have identified the newer uprobes tracing API as a candidate for building a replacement for ptrace, but ultimately rejected it due to lack of practical use and documentation. Building upon uprobes, we introduce plutonium-dbg, a Linux kernel module providing debugging facilities independent

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