Articles by Francisco Falcon

The March 2018 Android Security Bulletin includes fixes for 10 vulnerabilities in its Bluetooth stack, some of which were also independently discovered by Quarkslab, but were fixed while we were in the process of reporting them to Google (spoiler alert: we have reported a few more new Bluetooth vulnerabilities to the Android team — we'll disclose the details after they get fixed). This blogpost shows technical details for a couple of these fixed bugs, which can be triggered remotely and without any user interaction, as well as proof-of-concept code for them.

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.

On February 9, 2017, Natalie Silvanovich from Google Project Zero unrestricted access to P0's issue #983 [1], titled "Microsoft Edge: Use-after-free in TypedArray.sort", which got assigned CVE-2016-7288 and was patched as part of Microsoft security bulletin MS16-145 [2] during December 2016. In this blog post we discuss how I managed to exploit this UAF issue to obtain remote code execution on MS Edge.

On September 13th, 2016 Microsoft released security bulletin MS16-104 [1], which addresses several vulnerabilities affecting Internet Explorer. One of those vulnerabilities is CVE-2016-3353, a security feature bypass bug in the way .URL files are handled. This security issue does not allow for remote code execution by itself; instead, it allows attackers to bypass a security warning in attacks involving user interaction. In this blogpost we discuss the whole process, from reverse engineering the patch to building a Proof-of-Concept for this vulnerability.