Articles by Francisco Falcon

This blog post provides details about nine vulnerabilities affecting the IPv6 network protocol stack of EDK II, TianoCore's open source reference implementation of UEFI.

In this blog post we discuss how to debug Windows' Isolated User Mode (IUM) processes, also known as Trustlets, using the virtual TPM of Microsoft Hyper-V as our target.

In this blog post we discuss the details of two vulnerabilities we discovered in the Trusted Platform Module (TPM) 2.0 reference implementation code. These two vulnerabilities, an out-of-bounds write (CVE-2023-1017) and an out-of-bounds read (CVE-2023-1018), affected several TPM 2.0 software implementations (such as the ones used by virtualization software) as well as a number of hardware TPMs.

In this blog post we analyze a heap overflow vulnerability we discovered in the IPv6 stack of OpenBSD, more specifically in its slaacd daemon. This issue, whose root cause can be found in the mishandling of Router Advertisement messages containing a DNSSL option with a malformed domain label, was patched by OpenBSD on March 21, 2022. A proof-of-concept to reproduce the vulnerability is provided.

In this blog post we analyze a denial of service vulnerability affecting the IPv6 stack of Windows. This issue, whose root cause can be found in the mishandling of IPv6 fragments, was patched by Microsoft in their February 2021 security bulletin.

This blog post provides details about four vulnerabilities we found in the IPv6 stack of FreeBSD, more specifically in rtsold(8), the router solicitation daemon. The bugs affected all supported versions of FreeBSD, and the most severe of them could allow an attacker attached to the same physical link to gain remote code execution as root on vulnerable systems. The vulnerabilities were discovered and reported to FreeBSD Security Team in November 2020. FreeBSD issued fixes for these bugs on December 1st, 2020 along with security advisory FreeBSD-SA-20:32.rtsold.

Microsoft is currently working on Xtended Flow Guard (XFG), an evolved version of Control Flow Guard (CFG), their own control flow integrity implementation. XFG works by restricting indirect control flow transfers based on type-based hashes of function prototypes. This blog post is a deep dive into how the MSVC compiler generates those XFG function prototype hashes.

This blog post analyzes the vulnerability known as "Bad Neighbor" or CVE-2020-16898, a stack-based buffer overflow in the IPv6 stack of Windows, which can be remotely triggered by means of a malformed Router Advertisement packet.

On September 2018, FreeBSD published the security advisory FreeBSD-SA-18:12, fixing a kernel memory disclosure vulnerability affecting all the supported versions of this operating system.

Earlier this year, on March 2018, we published a blog post detailing 2 vulnerabilities in the Android Bluetooth stack, which were independently discovered by Quarkslab, but were fixed in the March 2018 Android Security Bulletin while we were in the process of reporting them to Google.