Recent content on pwning.systems
Earlier this year, I discovered a flaw in XNU, which is the kernel that Apple uses on both macOS and iOS. While it’s not a particularly complicated flaw, I wanted to explain how I discovered it and how it works, both so that I can motivate others and so that they can learn from my discovery. Within the memdev.c file (the ramdisk device driver), I found the source of the vulnerability, which…
It is likely that we have all seen PHP filters that prevent us from encountering vulnerabilities. Here in this blog post, I’ll walk you through my thought process for bypassing a filter by looking for a bug in the filter itself in order to reach a bug! Let’s pretend we have the following code, which passes some user-input to filter_var() and uses the FILTER_VALIDATE_DOMAIN or FILTER…
Despite the fact that it is not a ‘real’ vulnerability, escaping privileged Docker containers is nevertheless pretty funny. And because there will always be people who will come up with reasons or excuses to run a privileged container (even though you really shouldn’t), this could really be handy at some point in the future. As a result of the recent discovery of the…
I imagine we’ve all heard about the recent “Sequoia” bug discovered by the Qualys Research team, identified by CVE-2021-33909. It’s a fascinating bug caused by a size_t to int conversion. According to the analysis, seq_dentry attempts to convert a size_t to an int by sending size_t size to the dentry_path function, which expects a signed integer. Assuming the architecture…
Mistreatment by Apple Security is unfortunately something you’re likely to come across on a regular basis. Usually this concerns people that conduct free work for Apple in their spare time by auditing their assets. Despite Apple’s website claiming the opposite, you’ll frequently find things like quiet patching, no credit, no bounties, and an appalling lack of communication. This…
Following up on my first blog post, I’ve received a few requests to write about setting up a debugging environment; however, since everybody uses different emulators and so on, I’ll mainly focus on which config options are useful! You must first obtain the kernel sources for your preferred version before you can set up a kernel suitable for debugging. We’ll have to decompress it…
Here are some links to a few of my favorite websites. Darkscience - Nice IRC network SmashTheStack - Nice wargames and community! OverTheWire - Another set of great wargames Dustri.org - Cool person that writes great blogposts :)
I’m writing this post because I often hear that kernel exploitation is intimidating or difficult to learn. As a result, I’ve decided to start a series of basic bugs and exercises to get you started! Prerequisites Knowledge of the Linux command line Knowing how to read and write basic C may be beneficial Being able to debug with the help of a virtual computer or another system Able to…
The following are some of the bugs I discovered: 2025 CVE-2025-32313: In UsageEvents of UsageEvents.java, there is a possible out of bounds write due to an incorrect bounds check. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation. 2024 CVE-2024-56626: In the Linux kernel, the following vulnerability has…
Hello and welcome to my blog! I’m Jordy Zomer and this is my personal space to share my thoughts, research, and write-ups (assuming I don’t have any memory leaks). Expect to see posts covering: Static Analysis Fuzzing Reverse Engineering Binary Exploitation Vulnerability Research (mainly OSS-focused) Feel free to connect with me over on Twitter/X, or drop me an email at jordy [a-t]…