Ghost in the PPL Part 3: LSASS Memory Dump

Following my failed attempt to achieve arbitrary code execution within a protected LSASS process using the BYOVDLL technique and an N-day exploit in the KeyIso service, I took a step back, and reconsidered my life choices opted for a less ambitious solution: a (not so) simple memory dump. After all, when it comes to LSASS, we are mostly interested in extracting credentials stored in memory.

Continue reading Ghost in the PPL Part 3: LSASS Memory Dump

Ghost in the PPL Part 2: From BYOVDLL to Arbitrary Code Execution in LSASS

In the previous part, I showed how a technique called “Bring Your Own Vulnerable DLL” (BYOVDLL) could be used to reintroduce known vulnerabilities in LSASS, even when it’s protected. In this second part, I’m going to discuss the strategies I considered and explored to improve my proof-of-concept, and hopefully achieve arbitrary code execution.

Continue reading Ghost in the PPL Part 2: From BYOVDLL to Arbitrary Code Execution in LSASS

Insomni’hack 2024 – Bash to the Future writeup

The Challenge

You have been contracted to help COPERNIC Inc spot the light on a potential compromise. It seems that one of their scientists has been spied through a 20 years old malware… And fortunately, Zeus was on your side since the 4 Gb snapshot was carried out at the best possible time to facilitate your analysis.

Continue reading Insomni’hack 2024 – Bash to the Future writeup

A Deep Dive into TPM-based BitLocker Drive Encryption

When I investigated CVE-2022-41099, a BitLocker Drive Encryption bypass through the Windows Recovery Environment (WinRE), the fact that the latter was able to transparently access an encrypted drive without requiring the recovery password struck me. My initial thought was that there had to be a way to reproduce this behavior and obtain the master key from the Recovery Environment (WinRE). The outcome of a generic BitLocker bypass was too tempting not to explore this idea…

Continue reading A Deep Dive into TPM-based BitLocker Drive Encryption

CVE-2022-41099 – Analysis of a BitLocker Drive Encryption Bypass

In November 2022, an advisory was published by Microsoft about a BitLocker bypass. This vulnerability caught my attention because the fix required a manual operation by users and system administrators, even after installing all the security updates. Couple this with the fact that the procedure was not well documented initially, and you have the perfect recipe for disaster.

This is typically the kind of vulnerability you do not want to deal with when you are in charge of a large fleet of workstations and laptops. However, on the other side of things, hard to patch vulnerabilities such as this one usually offer the best opportunities for red teamers and the like. This is where my journey investigating this bug and learning more about TPM-based BitLocker Drive Encryption began.

Continue reading CVE-2022-41099 – Analysis of a BitLocker Drive Encryption Bypass

Insomni’hack 2023 CTF Teaser – DoH ! writeup

For this 2023 edition, i chose to focus on the DoH (DNS Over Https) protocol because it has gained popularity for attackers as a command and control (C2) communication channel for hiding DNS traffic through HTTPS rather than using the traditional DNS tunneling. In this post, i will describe in details how to solve the challenge.

Continue reading Insomni’hack 2023 CTF Teaser – DoH ! writeup