Security research, CTF writeups, and more.https://underdunn.com/https://underdunn.com/series/windows-drivers-p8-smep-bypass/https://underdunn.com/series/windows-drivers-p8-smep-bypass/Porting the HEVD buffer overflow exploit to 64-bit Windows 8.1 and using ROP to bypass Supervisor Mode Execution Prevention.Wed, 20 Aug 2025 01:45:44 GMTSerieshttps://underdunn.com/series/windows-drivers-p7-buffer-overflow-win7/https://underdunn.com/series/windows-drivers-p7-buffer-overflow-win7/Developing a kernel stack buffer overflow exploit against HackSysExtremeVulnerableDriver on 32-bit Windows 7 with token-stealing shellcode.Fri, 15 Aug 2025 18:37:47 GMTSerieshttps://underdunn.com/research/windows-kernel-debugger/https://underdunn.com/research/windows-kernel-debugger/Guide to setting up both network and serial kernel debugging for Windows VMs in VMware Workstation Pro using WinDbg.Wed, 06 Aug 2025 18:59:28 GMTResearchhttps://underdunn.com/series/windows-drivers-p6-debugging-drivers/https://underdunn.com/series/windows-drivers-p6-debugging-drivers/Setting up a kernel debugger, loading a driver into IDA, rebasing the text segment, and tracing IRPs through a live driver.Wed, 06 Aug 2025 15:35:29 GMTSerieshttps://underdunn.com/series/windows-drivers-p5-basic-driver-function/https://underdunn.com/series/windows-drivers-p5-basic-driver-function/Building a driver that handles DeviceIoControl requests and exploring buffered, direct, and neither I/O methods.Tue, 22 Jul 2025 17:20:31 GMTSerieshttps://underdunn.com/series/windows-drivers-p4-interacting-with-driver/https://underdunn.com/series/windows-drivers-p4-interacting-with-driver/How IRPs, IO Stack Locations, and dispatch functions work together to let user-mode applications communicate with kernel drivers.Sun, 20 Jul 2025 15:46:16 GMTSerieshttps://underdunn.com/series/windows-drivers-p3-minimum-viable-driver/https://underdunn.com/series/windows-drivers-p3-minimum-viable-driver/Setting up a driver development environment in Visual Studio and writing a minimal kernel driver that loads and unloads.Thu, 17 Jul 2025 23:45:29 GMTSerieshttps://underdunn.com/series/windows-drivers-p2-whats-a-driver/https://underdunn.com/series/windows-drivers-p2-whats-a-driver/A history of Windows drivers and an explanation of what they are, the different types, and how they fit into the modern Windows kernel.Wed, 16 Jul 2025 21:14:58 GMTSerieshttps://underdunn.com/series/windows-drivers-p1-overview/https://underdunn.com/series/windows-drivers-p1-overview/Introduction to the Windows driver exploitation series — who it's for, what tools you'll need, and why drivers are a great target.Tue, 15 Jul 2025 00:07:00 GMTSerieshttps://underdunn.com/writeups/the-leg/https://underdunn.com/writeups/the-leg/Writeup for a Meltdown-style speculative execution exploit challenge on theLEG architecture, authored for UMass CTF 2025.Sun, 20 Apr 2025 20:00:00 GMTWriteupshttps://underdunn.com/research/signal-windows-decryption/https://underdunn.com/research/signal-windows-decryption/Step-by-step guide to decrypting the Signal desktop database on Windows, covering both the old plaintext key method and the new DPAPI-protected key.Mon, 27 Jan 2025 04:28:04 GMTResearchhttps://underdunn.com/writeups/signaling-victorious/https://underdunn.com/writeups/signaling-victorious/Decrypting Signal messages and extracting credentials from a Windows memory dump to solve the HTB Binary Badlands 2024 forensics challenge.Thu, 19 Dec 2024 01:31:50 GMTWriteupshttps://underdunn.com/writeups/one-step-closer/https://underdunn.com/writeups/one-step-closer/Solving the One Step Closer challenge from the HTB University CTF 2023.Tue, 17 Oct 2023 16:23:50 GMTWriteupshttps://underdunn.com/writeups/zombienet/https://underdunn.com/writeups/zombienet/Investigating persistent access on a compromised OpenWRT router image from the HTB Uni CTF 2023.Tue, 17 Oct 2023 16:23:50 GMTWriteups