Skip to content

{ Category Archives } windows 7

Disclosing stack data (stack frames, GS cookies etc.) from the default heap on Windows

In the previous blog post, I discussed a modest technique to “fix” the default process heap in order to prevent various Windows API functions from crashing, by replacing the corresponding field in PEB (Process Environment Block) with a freshly created heap. This of course assumes that the attacker has already achieved arbitrary code execution, or is […]

Windows user-mode exploitation trick – refreshing the main process heap

During the weekend of May 21-23 (directly after the CONFidence CTF that we organized with Dragon Sector), qualifications to the famous DEF CON CTF 2016 took place. We obviously participated in what is probably the most binary heavy, challenging and competitive CTF of the year, eventually ending up 9th on the final scoreboard, which was sufficient […]

44CON slides and details about further Windows kernel font vulnerabilities are out

Since my last blog post and the REcon conference in June, I have continued working on font security, especially in the area of Windows kernel and font engines derived from the Adobe Type Manager Font Driver. More specifically, I moved from manually auditing PostScript Charstring implementations to running automated fuzz-testing of the overall font-handling code; after […]

Results of my recent PostScript Charstring security research unveiled

Some months ago, I started reverse engineering and investigating the security posture of the Adobe Type Manager Font Driver (ATMFD.DLL) module, which provides support for Type 1 and OpenType fonts in the Windows kernel since Windows NT 4.0, and remains there up to this day in Windows 8.1. Specifically, I focused on the handling of […]

Windows System Call and CSR API tables updated

Having the first spare weekend in a really long time, I have decided it was high time to update some (all) of the tables related to Windows system calls and CSR API I once created and now try to maintain. This includes NT API syscalls for the 32-bit and 64-bit Intel platforms, win32k.sys syscalls for […]

ZeroNights 2013 and NTVDM vulnerabilities

Just yesterday I had the pleasure to speak at a highly hacking-oriented Russian conference, ZeroNights, for the second time (see my “ZeroNights slides, Hack In The Box Magazine #9 and other news” post from last year). The conference itself has been great so far – several interesting and inspiring talks, lots of leet Russian hackers […]

Windows win32k.sys menus and some “close, but no cigar” bugs

Welcome after one of the more lengthy breaks in the blog’s activity. Today, I would like to discuss none other than several interesting weaknesses around the implementation of menus (like, window menus) in the core component of the Microsoft Windows kernel – the infamous win32k.sys driver, also known as the “Java of Windows” in terms […]

Black Hat USA 2013, Bochspwn, slides and pointers

(Collaborative post by Mateusz “j00ru” Jurczyk and Gynvael Coldwind) Two weeks ago (we’re running late, sorry!) Gynvael and I had the pleasure to attend one of the largest, most technical and renowned conferences in existence – Black Hat 2013 in Las Vegas, USA. The event definitely stood up to our expectations – the city was purely […]

Changing the cursor shape in Windows proven difficult by NVIDIA (and AMD)

If you work in the software engineering or information security field, you should be familiar with all sorts of software bugs – the functional and logical ones, those found during the development and internal testing along with those found and reported by a number of complaining users, those that manifest themselves in the form of […]

Kernel double-fetch race condition exploitation on x86 – further thoughts

(Collaborative post by Mateusz “j00ru” Jurczyk and Gynvael Coldwind) It was six weeks ago when we first introduced our effort to locate and eliminate the so-called double fetch (e.g. time-of-check-to-time-of-use during user-land memory access) vulnerabilities in operating system kernels through CPU-level operating system instrumentation, a project code-named “Bochspwn” as a reference to the x86 emulator used (bochs: The Open […]