The Problems and Promise of WebAssembly

Posted by Natalie Silvanovich, Project Zero WebAssembly is a format that allows code written in assembly-like instructions to be run from JavaScript. It has recently been implemented in all four major browsers. We reviewed each browser’s WebAssembly implementation and found three vulnerabilities...

First handset with MTE on the market

By Mark Brand, Google Project Zero Introduction It's finally time for me to fulfill a long-standing promise. Since I first heard about ARM's Memory Tagging Extensions, I've said to far too many people at this point to be able to back out… that I'd immediately switch to the first available device...

The Definitive Guide on Win32 to NT Path Conversion

Posted by James Forshaw, path’ological reverse engineer. How the Win32 APIs process file paths on Windows NT is a tale filled with backwards compatibility hacks, weird behaviour, and beauty†. Incorrect handling of Win32 paths can lead to security vulnerabilities. This blog post is to try and give...

Exploiting NVMAP to escape the Chrome sandbox - CVE-2014-5332

Posted by Lee Campbell, Graphics Pwning Unit This guest post continues Project Zero’s practice of promoting excellence in security research on the Project Zero blog Background: Chrome for Android implements a very different sandbox model to that of Chrome for Linux. One of the platform features w...

Race you to the kernel!

Posted by Ian Beer of Google Project Zero The OS X and iOS kernel code responsible for loading a setuid root binary invalidates the old task port after first swapping the new virtual memory map pointer into the old task object, leaving a short race window where you can manipulate the memory of an...

The poisoned NUL byte, 2014 edition

Posted by Chris Evans, Exploit Writer Underling to Tavis Ormandy Back in this 1998 post to the Bugtraq mailing list, Olaf Kirch outlined an attack he called “The poisoned NUL byte”. It was an off-by-one error leading to writing a NUL byte outside the bounds of the current stack frame. On i386...

A day^W^W Several months in the life of Project Zero - Part 2: The Chrome exploit of suffering

Posted by Sergei Glazunov and Mark Brand, Project Zero Introduction After we’d understood how the bug worked, and had passed on those details to Chrome to help them get started on a fix, we went back to our other projects. This bug remained a topic of discussion, and eventually we ran out of...

Adventures in Video Conferencing Part 1: The Wild World of WebRTC

Posted by Natalie Silvanovich, Project Zero Over the past five years, video conferencing support in websites and applications has exploded. Facebook, WhatsApp, FaceTime and Signal are just a few of the many ways that users can make audio and video calls across networks. While a lot of research ha...

Over The Air: Exploiting Broadcom’s Wi-Fi Stack (Part 2)

Posted by Gal Beniamini, Project Zero In this blog post we'll continue our journey into gaining remote kernel code execution, by means of Wi-Fi communication alone. Having previously developed a remote code execution exploit giving us control over Broadcom’s Wi-Fi SoC, we are now left with the ta...

Bypassing Administrator Protection by Abusing UI Access

Posted by James Forshaw In my last blog post I introduced the new Windows feature, Administrator Protection and how it aimed to create a secure boundary for UAC where one didn’t exist. I described one of the ways I was able to bypass the feature before it was released. In total I found 9 bypasses...

A walk through Project Zero metrics

Posted by Ryan Schoen, Project Zero tl;dr In 2021, vendors took an average of 52 days to fix security vulnerabilities reported from Project Zero. This is a significant acceleration from an average of about 80 days 3 years ago. In addition to the average now being well below the 90-day deadline, w...

MMS Exploit Part 2: Effective Fuzzing of the Qmage Codec

Posted by Mateusz Jurczyk, Project Zero This post is the second of a multi-part series capturing my journey from discovering a vulnerable little-known Samsung image codec, to completing a remote zero-click MMS attack that worked on the latest Samsung flagship devices. New posts will be published ...

Down the Rabbit-Hole...

Posted by Tavis Ormandy, Security Research Over-Engineer. “Sometimes, hacking is just someone spending more time on something than anyone else might reasonably expect.”1 I often find it valuable to write simple test cases confirming things work the way I think they do. Sometimes I can’t explain t...

Finding and exploiting ntpd vulnerabilities

Posted by Stephen Röttger, Time Lord Foreword by Chris Evans: this post by Stephen represents the first Project Zero guest blog post. From time to time, we’ll be featuring guest blog posts for top-tier security research. In this instance, we’ve been impressed by the remotely exploitable nature of...

KTRW: The journey to build a debuggable iPhone

Posted by Brandon Azad, Project Zero In my role here at Project Zero, I do not use some of the tooling used by some external iOS security researchers, in particular development-fused iPhones with hardware debugging capabilities like JTAG enabled. I believe that access to such devices puts those w...

Over The Air - Vol. 2, Pt. 1: Exploiting The Wi-Fi Stack on Apple Devices

Posted by Gal Beniamini, Project Zero Earlier this year we performed research into Broadcom’s Wi-Fi stack. Due to the ubiquity of Broadcom’s stack, we chose to conduct our prior research through the lens of one affected family of products -- the Android ecosystem. To paint a more complete picture...

One font vulnerability to rule them all #3: Windows 8.1 32-bit sandbox escape exploitation

Posted by Mateusz Jurczyk of Google Project Zero This is part 3 of the “One font vulnerability to rule them all” blog post series. In the previous posts, we introduced the “blend” PostScript operator vulnerability, discussed the Charstring primitives necessary to fully control the stack contents...

What is a "good" memory corruption vulnerability?

Posted by Chris Evans, register whisperer. Part 1 of 4. There are a lot of memory corruption vulnerabilities in software, but not all are created equal. To a certain degree, the “usefulness” of a given memory corruption vulnerability is determined by how reliably it might be exploited. In some...

Life After the Isolated Heap

Posted by Natalie Silvanovich, Mourner of Lost Exploits Over the past few months, Adobe has introduced a number of changes to the Flash Player heap with the goal of reducing the exploitability of certain types of vulnerabilities in Flash, especially use-after-frees. I wrote an exploit involving t...

Exploiting a Leaked Thread Handle

Posted by logged on user, James Forshaw. Once in awhile you’ll find a bug that allows you to leak a handle opened in a privileged process into a lower privileged process. I found just such a bug in the Secondary Logon service on Windows, which was fixed this month as MS16-032. The bug allowed you...

One Byte to rule them all

Posted by Brandon Azad, Project Zero One Byte to rule them all, One Byte to type them, One Byte to map them all, and in userspace bind them -- Comment above vmmapcopyt For the last several years, nearly all iOS kernel exploits have followed the same high-level flow: memory corruption and fake Mac...

Lifting the (Hyper) Visor: Bypassing Samsung’s Real-Time Kernel Protection

Posted by Gal Beniamini, Project Zero Traditionally, the operating system’s kernel is the last security boundary standing between an attacker and full control over a target system. As such, additional care must be taken in order to ensure the integrity of the kernel. First, when a system boots, t...

MMS Exploit Part 4: MMS Primer, Completing the ASLR Oracle

Posted by Mateusz Jurczyk, Project Zero This post is the fourth of a multi-part series capturing my journey from discovering a vulnerable little-known Samsung image codec, to completing a remote zero-click MMS attack that worked on the latest Samsung flagship devices. New posts will be published ...

Feedback and data-driven updates to Google’s disclosure policy

Posted by Chris Evans and Ben Hawkes, Project Zero; Heather Adkins, Matt Moore and Michal Zalewski, Google Security; Gerhard Eschelbeck, Vice President, Google Security Disclosure deadlines have long been an industry standard practice. They improve end-user security by getting security patches to...

MTE As Implemented, Part 2: Mitigation Case Studies

By Mark Brand, Project Zero Background In 2018, in the v8.5a version of the ARM architecture, ARM proposed a hardware implementation of tagged memory, referred to as MTE Memory Tagging Extensions. In Part 1 we discussed testing the technical and implementation limitations of MTE on the hardware...

The State of State Machines

Posted by Natalie Silvanovich, Project Zero On January 29, 2019, a serious vulnerability was discovered in Group FaceTime which allowed an attacker to call a target and force the call to connect without user interaction from the target, allowing the attacker to listen to the target’s surroundings...

Breaking the Sound Barrier Part I: Fuzzing CoreAudio with Mach Messages

Guest post by Dillon Franke, Senior Security Engineer, 20% time on Project Zero Every second, highly-privileged MacOS system daemons accept and process hundreds of IPC messages. In some cases, these message handlers accept data from sandboxed or unprivileged processes. In this blog post, I’ll...

Examining Pointer Authentication on the iPhone XS

Posted by Brandon Azad, Project Zero In this post I examine Apple's implementation of Pointer Authentication on the A12 SoC used in the iPhone XS, with a focus on how Apple has improved over the ARM standard. I then demonstrate a way to use an arbitrary kernel read/write primitive to forge kernel...

(^Exploiting)\s*(CVE-2015-0318)\s*(in)\s*(Flash$)

Posted by Mark Brand, Irregular Expressionist So; issue 199/PSIRT-3161/CVE-2015-0318. Quick summary - it’s a bug in the PCRE regex engine as used in Flash. Note that the published version of the avmplus code is significantly out of date; there are a number of other vulnerabilities present that ha...

Windows Exploitation Techniques: Dangling COM Object Registrations

Posted by James Forshaw This short blog post is about abusing a privilege escalation bug that Microsoft recently fixed in Windows, CVE-2026-66804, that I and 14 others reported. This issue is an incomplete fix for CVE-2026-50343, a bug dubbed “Dark Elevator” by Calif. The root cause of the bug wa...

Policy and Disclosure: 2025 Edition

Posted by Tim Willis, Google Project Zero In 2021, we updated our vulnerability disclosure policy to the current "90+30" model. Our goals were to drive faster yet thorough patch development, and improve patch adoption. While we’ve seen progress, a significant challenge remains: the time it takes...

Effective Fuzzing: A Dav1d Case Study

Guest post by Nick Galloway, Senior Security Engineer, 20% time on Project Zero Late in 2023, while working on a 20% project with Project Zero, I found an integer overflow in the dav1d AV1 video decoder. That integer overflow leads to an out-of-bounds write to memory. Dav1d 1.4.0 patched this, an...

task_t considered harmful

Posted by Ian Beer, Project Zero This post discusses a design issue at the core of the XNU kernel which powers iOS and MacOS. Apple have shipped two iterations of mitigations followed yesterday by a large refactor in MacOS 10.12.1/iOS 10.1. We’ll look at the bugs, how they can be exploited to...

Breaking the Sound Barrier, Part II: Exploiting CVE-2024-54529

Posted by Dillon Franke, Google Information Security Engineering, 20% time on Project Zero In the first part of this series, I detailed my journey into macOS security research, which led to the discovery of a type confusion vulnerability CVE-2024-54529 and a double-free vulnerability CVE-2025-312...

MTE As Implemented, Part 1: Implementation Testing

By Mark Brand, Project Zero Background In 2018, in the v8.5a version of the ARM architecture, ARM proposed a hardware implementation of tagged memory, referred to as MTE Memory Tagging Extensions. Through mid-2022 and early 2023, Project Zero had access to pre-production hardware implementing thi...

Exploiting Android Messengers with WebRTC: Part 1

Posted by Natalie Silvanovich, Project Zero This is a three-part series on exploiting messenger applications using vulnerabilities in WebRTC. This series highlights what can go wrong when applications don't apply WebRTC patches and when the communication and notification of security issues breaks...

Welcome to the new Project Zero Blog

Posted by Natalie Silvanovich While on Project Zero, we aim for our research to be leading-edge, our blog design was … not so much. We welcome readers to our shiny new blog! For the occasion, we asked members of Project Zero to dust off old blog posts that never quite saw the light of day. And...

Escaping the Chrome Sandbox with RIDL

Guest blog post by Stephen Röttger tl;dr: Vulnerabilities that leak cross process memory can be exploited to escape the Chrome sandbox. An attacker is still required to compromise the renderer prior to mounting this attack. To protect against attacks on affected CPUs make sure your microcode is u...

The story of Adobe Reader symbols

Posted by Mateusz Jurczyk, Project Zero Modern day security analysis of client applications is often hindered by the inaccessibility of their source code and other aids such as debug symbols. As a result, it is necessary to perform completely black-box reverse engineering of the software, in orde...

A 0-click exploit chain for the Pixel 9 Part 3: Where do we go from here?

Posted by Natalie Silvanovich While our previous two blog posts provided technical recommendations for increasing the effort required by attackers to develop 0-click exploit chains, our experience finding, reporting and exploiting these vulnerabilities highlighted some broader issues in the Andro...

Thinking Outside The Box [dusted off draft from 2017]

Posted by Jann Horn Preface Hello from the future! This is a blogpost I originally drafted in early 2017. I wrote what I intended to be the first half of this post about escaping from the VM to the VirtualBox host userspace process with CVE-2017-3558, but I never got around to writing the second...

Announcing the Fuzzilli Research Grant Program

Posted by Samuel Groß, Project Zero Project Zero’s mission is to make 0-day hard in order to improve end-user security. We attack this problem in different ways, including supporting other security researchers. While Google currently offers research grants, they are limited to academics and those...

365 Days Later: Finding and Exploiting Safari Bugs using Publicly Available Tools

Posted by Ivan Fratric, Google Project Zero Around a year ago, we published the results of research about the resilience of modern browsers against DOM fuzzing, a well-known technique for finding browser bugs. Together with the bug statistics we also published Domato, our DOM fuzzing tool that wa...

Chrome OS exploit: one byte overflow and symlinks

The following article is an guest blog post from an external researcher i.e. the author is not a Project Zero or Google researcher. This post is about a Chrome OS exploit I reported to Chrome VRP in September. The Project Zero folks were nice to let me do a guest post about it, so here goes. The...

How to Compromise the Enterprise Endpoint

Posted by Tavis Ormandy. Symantec is a popular vendor in the enterprise security market, their flagship product is Symantec Endpoint Protection. They sell various products using the same core engine in several markets, including a consumer version under the Norton brand. Today we’re publishing...

Owning Internet Printing - A Case Study in Modern Software Exploitation

Guest posted by Neel Mehta [email protected] - June 19th, 2015 Abstract Modern exploit mitigations draw attackers into a game of diminishing marginal returns. With each additional mitigation added, a subset of software bugs become unexploitable, and others become difficult to exploit, requiring...

A Deep Dive into the GetProcessHandleFromHwnd API

Posted by James Forshaw In my previous blog post I mentioned the GetProcessHandleFromHwnd API. This was an API I didn’t know existed until I found a publicly disclosed UAC bypass using the Quick Assist UI Access application. This API looked interesting so I thought I should take a closer look. I...

Windows Exploitation Techniques: Winning Race Conditions with Path Lookups

Posted by James Forshaw This post was originally written in 2016 for the Project Zero blog. However, in the end it was published separately in the journal PoC||GTFOissue 13 as well as in the second volume of the printed version. In honor of our new blog we’re republishing it on this blog and...

Simple macOS kernel extension fuzzing in userspace with IDA and TinyInst

Posted by Ivan Fratric, Google Project Zero Recently, one of the projects I was involved in had to do with video decoding on Apple platforms, specifically AV1 decoding. On Apple devices that support AV1 video format starting from Apple A17 iOS / M3 macOS, decoding is done in hardware. However,...

Searching statically-linked vulnerable library functions in executable code

Helping researchers find 0ld days Posted by Thomas Dullien, Project Zero Executive summary Software supply chains are increasingly complicated, and it can be hard to detect statically-linked copies of vulnerable third-party libraries in executables. This blog post discusses the technical details ...