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...

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...

Exploiting null-dereferences in the Linux kernel

Posted by Seth Jenkins, Project Zero For a fair amount of time, null-deref bugs were a highly exploitable kernel bug class. Back when the kernel was able to access userland memory without restriction, and userland programs were still able to map the zero page, there were many easy techniques for...

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...

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...

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...

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 ...

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 ...

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...

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...

How to unc0ver a 0-day in 4 hours or less

By Brandon Azad, Project Zero At 3 PM PDT on May 23, 2020, the unc0ver jailbreak was released for iOS 13.5 the latest signed version at the time of release using a zero-day vulnerability and heavy obfuscation. By 7 PM, I had identified the vulnerability and informed Apple. By 1 AM, I had sent App...

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...

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...

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...

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...

The Great DOM Fuzz-off of 2017

Posted by Ivan Fratric, Project Zero Introduction Historically, DOM engines have been one of the largest sources of web browser bugs. And while in the recent years the popularity of those kinds of bugs in targeted attacks has somewhat fallen in favor of Flash which allows for cross-browser exploi...

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...

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...

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...

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...

(^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...

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...

A 0-click exploit chain for the Pixel 9 Part 1: Decoding Dolby

Posted by Natalie Silvanovich Over the past few years, several AI-powered features have been added to mobile phones that allow users to better search and understand their messages. One effect of this change is increased 0-click attack surface, as efficient analysis often requires message media to...

Blasting Past Webp

An analysis of the NSO BLASTPASS iMessage exploit Posted by Ian Beer, Google Project Zero On September 7, 2023 Apple issued an out-of-band security update for iOS: Around the same time on September 7th 2023, Citizen Lab published a blog post linking the two CVEs fixed in iOS 16.6.1 to an "NSO Gro...

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...

More Mac OS X and iPhone sandbox escapes and kernel bugs

Posted by Ian Beer A couple of weeks ago Apple released OS X 10.9.5 and iOS 8 which fixed a number of sandbox escapes and privilege escalation bugs found by Project Zero. All-bar-one of these bugs were found via manual source code auditing where there was source and binary analysis where there...

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...

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...

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...

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...

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...

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...

One Perfect Bug: Exploiting Type Confusion in Flash

Posted by Natalie Silvanovich, Dazed and Type Confused For some attackers, it is important that an exploit be extremely reliable. That is to say, the exploit should consistently lead to code execution when it is run on a system with a known platform and Flash version. One way to create such an...

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...

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 ...

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...

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...

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...

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...

aPAColypse now: Exploiting Windows 10 in a Local Network with WPAD/PAC and JScript

by Ivan Fratric, Thomas Dullien, James Forshaw and Steven Vittitoe Intro Many widely-deployed technologies, viewed through 20/20 hindsight, seem like an odd or unnecessarily risky idea. Engineering decisions in IT are often made with imperfect information and under time pressure, and some odditie...

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...

Summary: MTE As Implemented

By Mark Brand, Project Zero In mid-2022, Project Zero was provided with access to pre-production hardware implementing the ARM MTE specification. This blog post series is based on that review, and includes general conclusions about the effectiveness of MTE as implemented, specifically in the...

Over The Air - Vol. 2, Pt. 3: Exploiting The Wi-Fi Stack on Apple Devices

Posted by Gal Beniamini, Project Zero In this blog post we’ll complete our goal of achieving remote kernel code execution on the iPhone 7, by means of Wi-Fi communication alone. After developing a Wi-Fi firmware exploit in the previous blog post, we are left with the task of using our newly...

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...

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...

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...

Policy and Disclosure: 2021 Edition

Posted by Tim Willis, Project Zero At Project Zero, we spend a lot of time discussing and evaluating vulnerability disclosure policies and their consequences for users, vendors, fellow security researchers, and software security norms of the broader industry. We aim to be a vulnerability research...