Skip to content

{ Category Archives } c++

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 […]

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 […]

A story of win32k!cCapString, or unicode strings gone bad

In the most recent blog post (“Fun facts: Windows kernel and guard pages”), we have learned how the code coverage of kernel routines referencing user-mode memory can be determined by taking advantage of the fact that kernel-mode code triggers guard page exceptions in the same way as user-mode does. Today, I will present how the […]

Nullcon 2012 CTF

(Collaborative post by Mateusz “j00ru” Jurczyk, Gynvael Coldwind and Adam Iwaniuk) Friday, the 7th of September 2012 we were supposed to play the CTF. Unfortunately, the competition was postponed for a later date at the last moment, due to some significant technical problems. Next day evening we accidentally discovered another CTF taking place – […]

Magus Ex Machina – a product of a 48h codejam

[Note: Collaborative post by Gynvael Coldwind and Mateusz “j00ru” Jurczyk] Five weeks ago, we have taken part in a fancy game-development competition aka Google GameJam 48h. As the name implies, the contest lasted for precisely two days; unfortunately, we were proven to lack supernatural powers and had to spend some of the precious time sleeping […]

PiXiEServ out for public

A few years back, we’ve been (i.e. j00ru and Gynvael) working on a bootkit-related project (some polish SecDay’09 presentation slides can be found here: Bootkit vs Windows.pdf). One of its basic requirements was the ability to load custom boot-“sectors” from an external host in the local network. Since the publicly available solutions required too much […]

CVE-2011-1281: A story of a Windows CSRSS Privilege Escalation vulnerability

Today, I would like to present a detailed description of the CVE-2011-1281 vulnerability [1], which was reported by me several months ago and patched today, together with four other bugs marked as the Elevation of Privileges class, on the occasion of the monthly Microsoft Patch Tuesday cycle (see Microsoft Security Bulletin MS11-056, a summary of […]

PE Import Table and custom DLL paths

Once upon a time, an interesting software vulnerability vector called DLL Hijacking became very popular, thanks to a Slovenian security research outfit – ACROS Security, as well as HD Moore and his DLL Hijacking Audit Kit. In short, the vulnerability class allowed an attacker to execute arbitrary code in the context of an application, which […]