Reverse Engineering the Win32k Type Isolation Mitigation

Given the popularity of GDI Bitmap objects for exploitation of kernel vulnerabilities -due to the fact that almost any kind of memory corruption vulnerability (except for NULL-writes) could be used to reliably gain arbitrary R/W primitives over the kernel memory by abusing Bitmaps- Microsoft decided to kill exploitation techniques based on Bitmaps. In order to do this, Windows 10 Fall Creators Update (also known as Windows 10 1709) introduced the Type Isolation feature, an exploitation mitigation in the Win32k subsystem, which splits the memory layout of SURFACE objects, the internal representation of Bitmaps on the kernel side. This blogpost takes a deep dive into the details of how Type Isolation is implemented.

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Slaying Dragons with QBDI

This article aims to present a simple use of our Dynamic Binary Instrumentation framework QBDI which has recently been publicly released following a talk at 34C3. We will resolve, step by step, a CTF challenge by analyzing an obfuscated binary using QBDI, thus showcasing some of the nice features it offers. This blog post was written last year during my internship at Quarkslab, where I discovered the wonderful (but not so simple) world of Dynamic Binary Instrumentation.

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Spectre is not a Bug, it is a Feature

What happens if one builds up on the Spectre vulnerability to implement a convoluted version of memcpy? From an obfuscator point-of-view, it unleashes a wide range of opportunities, which turn a definite bug into a fun[nk]y feature.

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Have fun with LIEF and Executable Formats

This blog post introduces new features of LIEF as well as some uses cases.

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Internship offers at Quarkslab for the 2017-2018 season

Quarkslab's new internships season is open! Like every year, we are looking for adventurous, motivated and courageous students, impatient to test their skills against real-life research and engineering problems. The topics we propose cover various aspects of the security field, and they all have in common being highly technical, complex and challenging. Be prepared to work hard for your own enjoyment: the satisfaction when overcoming such difficulties is priceless. As an intern, you will work among the amazing Qb crew, whose humour is also priceless.

All internships will take place in our main office in Paris, France. If you are coming from abroad, you will need a proper visa to be with us. At Quarkslab, we encourage remote working, but that does not apply to internships.

Last but not least, we usually train Padawans so that they remain with us once the training period is done, even if that does not mean the training is over :)

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Reverse engineering of the Nitro OBD2

This blog post presents the reverse engineering of an OBD2 dongle called "Nitro OBD2". It is advertised like this: "NitroOBD2 is a Chip Tuning Box which can be plugged into OBD2 connector of your car to increase the performance of your car." There are a lot of testimonies on the internet about this device being a fake, while other people say that is is really working. We wanted to reverse engineer it to check by ourselves.

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Mistreating Triton

Some experiments to mistreat the Triton concolic execution framework through simple forged C programs.

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Flash Dumping - Part I

First part of a blog post series about our approach to dump a flash chip. In this article we describe how to desolder the flash, design and build the corresponding breakout board.

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Vulnerabilities in High Assurance Boot of NXP i.MX microprocessors

This blog post provides details about two vulnerabilities found by Quarkslab's researchers Guillaume Delugré and Kévin Szkudłapski in the secure boot feature of the i.MX family of application processors built by NXP Semiconductors.

The bugs allow an attacker to subvert the secure boot process to bypass code signature verification and load and execute arbitrary code on i.MX application processors that have the High Assurance Boot feature enabled. These bugs affect 12 i.MX processor families.

The vulnerabilities were discovered and reported to the vendor in September 2016 and the technical details included in this blogpost were disclosed in a joint Quarkslab-NXP presentation at the Qualcomm Mobile Security Summit 2017 in May 19th, 2017. National computer emergency response teams (CERTs) from 4 countries were informed about the issues in March, 2017.

NXP has issued an Engineering Bulletin and two Errata documents (EB00854, ERR010872 and ERR0108873 respectively) providing a brief description of both vulnerabilities, the list of affected processor models along with resolution plans and possible mitigations.

In the rest of the blogpost we describe the relevant features in i.MX processors and the vulnerabilities affecting them.

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Reverse Engineering Samsung S6 SBOOT - Part II

In my previous article , I explained how to load Samsung's proprietary bootloader SBOOT into IDA Pro. The journey to the TEE OS continues in this second article which describes two techniques to locate Trustonic's TEE <t-base in the binary blob.

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