voidsec2022-03-10T14:42:04+01:00With this blog post I’d like to sum up my year-long Windows Drivers research; share and detail my own methodology for reverse engineering (WDM) Windows drivers, finding some possible vulnerable code paths as well as understanding their exploitability. I've tried to make it as "noob-friendly" as possible, documenting all the steps I usually perform during my research and including a bonus exercise for the readers.
Setting up the lab
While in the past, setting up a lab for kernel debugging was a...
voidsec2022-01-14T08:55:49+01:00As part of my continuous security research journey, during this year I’ve spent a good amount of time reverse-engineering Windows drivers and exploiting kernel-mode related vulnerabilities.
While in the past there were (as far as I know), at least two good IDA plugins aiding in the reverse engineering process:
DriverBuddy of NCC Group.
win_driver_plugin of F-Secure.
unfortunately, nowadays, they are both rusty, out of date and broken on the latest version of IDA. They relied on external dependencies, were lacking documentation and...
Crucial Ballistix MOD Utility is a software product that can be used to customize and control gaming systems, specifically LED colours and patterns, memory, temperature, and overclock.
During my vulnerability research, I’ve discovered that this software utilizes a driver, MODAPI.sys, containing multiple vulnerabilities and allowing an attacker to achieve local privilege escalation from a low privileged user to NT AUTHORITY\SYSTEM.
This blog post is a re-post of the original article “Crucial’s MOD Utility LPE” that I have written for Yarix on YLabs.
Root Cause Analysis of a Printer’s Drivers Vulnerability CVE-2021-3438
voidsec2022-01-14T08:58:25+01:00Last week SentinelOne disclosed a "high severity" flaw in HP, Samsung, and Xerox printer's drivers (CVE-2021-3438); the blog post highlighted a vulnerable strncpy operation with a user-controllable size parameter but it did not explain the reverse engineering nor the exploitation phase of the issue. With this blog post, I would like to analyse the vulnerability and its exploitability.
This blog post is a re-post of the original article “Root Cause Analysis of a Printer's Driver Vulnerability” that I have written for...
voidsec2022-01-14T08:58:33+01:00At the beginning of the month, Sentinel One disclosed five high severity vulnerabilities in Dell’s firmware update driver.
As the described vulnerability appeared not too complicated to exploit, a lot of fellow security researchers started weaponizing it. I was one of, if not the first tweeting about weaponizing it into a _SEP_TOKEN_PRIVILEGES overwrite exploit, and with this blog post I would like to write down my thoughts process when dealing with n-day exploit writing. It’s a didactic blog post but keep...
voidsec2022-01-17T14:21:37+01:00The analysed sample is a malware employed by the Threat Actor known as Ragnarok. The ransomware is responsible for files’ encryption and it is typically executed, by the actors themselves, on the compromised machines. The name of the analysed executable is xs_high.exe, but others have been found used by the same ransomware family (such as xs_normal.exe and xs_remote.exe).
The configuration within the malware contains information regarding the encryption activities, from whitelisted countries to the contents of the ransom note. It is...
voidsec2022-01-14T09:00:18+01:00Last month we (last & VoidSec) took the amazing Windows Kernel Exploitation Advanced course from Ashfaq Ansari (@HackSysTeam) at NULLCON. The course was very interesting and covered core kernel space concepts as well as advanced mitigation bypasses and exploitation. There was also a nice CTF and its last exercise was: “Write an exploit for System Mechanics”; no further hints were given.
We took the challenge as that was a good time to test our newly acquired knowledge and understanding of the...
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.
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...
voidsec2022-01-14T09:04:08+01:00TL; DR: this blog post serves as an advisory for both:
CVE-2020-28054: An Authorization Bypass vulnerability affecting JamoDat – TSMManager Collector v. <= 188.8.131.52
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!
voidsec2022-01-14T09:05:26+01:00Banner 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),...