Fuzzing: FastStone Image Viewer & CVE-2021-26236

This blog post is a re-post of the original article “Fuzzing: FastStone Image Viewer & CVE-2021-26236” that I have written for Yarix on YLabs. Introduction In my precedent blog post I’ve introduced “fuzzing” from a theoretical point of view. As I’ve previously anticipated, today I’m going to disclose the fuzzing methodology, process and samples that led me to discover five different vulnerabilities in FastStone Image Viewer v.<=7.5. I’ll also go over the root cause analysis of CVE-2021-26236 and how to achieve Arbitrary...

Tivoli Madness

TL; DR: this blog post serves as an advisory for both: CVE-2020-28054: An Authorization Bypass vulnerability affecting JamoDat – TSMManager Collector v. <= 6.5.0.21 A Stack Based Buffer Overflow affecting IBM Tivoli Storage Manager - ITSM Administrator Client Command Line Administrative Interface (dsmadmc.exe) Version 5, Release 2, Level 0.1. Unfortunately, after I had one of the rudest encounters with an Hackerone’s triager, these are the takeaways: IBM Tivoli Storage Manager has reached its end of life support and will not be...

CVE-2020-1337 – PrintDemon is dead, long live PrintDemon!

Banner Image by Sergio Kalisiak TL; DR: I will explain, in details, how to trigger PrintDemon exploit and dissect how I’ve discovered a new 0-day; Microsoft Windows EoP CVE-2020-1337, a bypass of PrintDemon’s recent patch via a Junction Directory (TOCTOU). After Yarden Shafir’s & Alex Ionescu’s posts (PrintDemon, FaxHell) and their call to action, I’ve started diving into the PrintDemon exploit. PrintDemon is the catching name for Microsoft CVE-2020-1048: Windows Print Spooler Elevation of Privilege Vulnerability which is affecting (according to Microsoft),...

A tale of a kiosk escape: ‘Sricam CMS’ Stack Buffer Overflow

TL;DR: Shenzhen Sricctv Technology Sricam CMS (SricamPC.exe) <= v.1.0.0.53(4) and DeviceViewer (DeviceViewer.exe) <= v.3.10.12.0 (CVE-2019-11563) are affected by a local Stack Buffer Overflow. By creating a specially crafted "Username" and copying its value in the "User/mail" login field, an attacker will be able to gain arbitrary code execution in the context of the currently logged-in user. Please Note: by default, Sricam CMS requires elevation and runs in High Integrity mode; exploitation of the above software will result in a compromise of...

Tabletopia: from XSS to RCE

During this period of social isolation, a friend of mine proposed to play some online "board games". He proposed “Tabletopia”: a cool sandbox virtual table with more than 800 board games. Tabletopia is both accessible from its own website and from the Steam’s platform. While my friends decided to play from their browser, I’ve opted for the Steam version. We joined a room and started a game; at one point we were messing around with some in-game cards when , for no...

Windows Kernel Debugging & Exploitation Part1 – Setting up the lab

Recently I was thrilled with the opportunity to build a PoC for ms-14-066 vulnerability aka “winshock” (CVE-2014-6321). While that will be material for another blog post, in order to debug the vulnerability, I had to set up a lab with windows kernel mode debugging enabled. So, without any further ado, here my setup and the steps used in order to enable Windows Kernel Debug. Setup Host system: Windows 10 with VMware Workstation 15.1.0 (build-13591040) Guest systems: Windows 7 x86 ultimate sp1 (debugger) Windows...

The Curse of the Antivirus Solution

This is the main article for the VirIT Explorer Local Privilege Escalation Exploit's, if you are not interested in the methodology and the story behind this vulnerability you can directly jump to the end and reach the exploit section. As a penetration tester I've realized that Antivirus Solutions are often insecure, they can be easily bypassed and they do not fully protect your system; sometimes they also make you more vulnerable and this is the case. I will always recommend AV as...