Maxim Suhanov

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39 Posts

Computer forensics, computer forensics tool validation, etc.

https://dfir.ru
https://github.com/msuhanov/

🕊

Most FDE vendors/projects don't consider vectors requiring repeated physical access as a vulnerability.

But there is another side to this: an HDD/SSD firmware backdoor (or a network attacker injecting arbitrary data into a disk image booted over the network) has a way to inject attacker-controlled data into an encrypted volume despite code integrity controls like Secure Boot and TPM-based unlocks (the "Implementation and Implications of a Stealth Hard-Drive Backdoor" paper told us the opposite).

In one MSRC case, Microsoft agreed to treat the data-only attack against BitLocker from the storage path as a vulnerability.

CVE-2024-13745 in EDK II (likely, "WONTFIX"): "what you measure is not what you use".

The story about firmware measuring bytes different from ones being used. It affects PCR[5], so the severity is low (nobody cares about PCR[5] by default).

https://www.openwall.com/lists/oss-security/2026/05/29/2

oss-security - CVE-2024-13745, EDK II: several issues with partition table measurements

hi everyone

given one #bitlocker #0day is already out there, here's my own bitlocker 0day, I added it to my repo listing bitlocker attacks.

Introducing "ram leak": https://github.com/Wack0/bitlocker-attacks#ram-leak

As we all know, the boot environment allows booting from a ramdisk. This involves loading a file from disk into RAM, as expected.

However, "file" and "disk" can be arbitrarily chosen, and "disk" being a BitLocker encrypted partition is a supported scenario. Using another trick (same one used with bitpixie earlier) it's possible to get the keys derived without going through the legacy integrity validation checks too if relevant.

You can see where this is going. It's possible to leak any file from a bitlocker encrypted OS partition into RAM as long as you can get the keys derived (ie, TPM-only scenario).

The catch is that booting into the NT kernel marks that memory area as free so it could get overwritten there, but there are other ways to dump the memory area, and a PoC is included with my preferred method (it's only a PoC so just displays a hexdump of the first sector of the file)

The video shows successful exploitation in my test VM, it has secure boot enabled (you can tell because VMware shows an efi shell option on the boot menu when secure boot is disabled).

#infosec #windows

NotCVE-2026-0002: if you run two NetScalers in the high availability (HA/HA-INC) deployment, no SSH host key checks are performed between them, even when you followed every advice listed here: https://docs.netscaler.com/en-us/netscaler-adc-secure-deployment/configuration-guidelines/network-security (see: Set up secure communication between peer appliances)

The vendor reported that this issue has been fixed in 14.1-60.52.
No security advisory, CVE ID, release notes entry was published. Although this is a minor vulnerability, it is a vulnerability.

Network security | NetScaler® Secure Deployment Guide

Network security

My story of recovering cleared RDP logs from a completely unrelated EVTX file: https://dfir.ru/2026/01/26/windows-event-logs-were-cleared-but-resurrected-in-another-file/ #DFIR
Windows event logs were cleared, but resurrected in another file!

TL;DR: The Windows Event Logging Service contains a bug (use of uninitialized memory) that sometimes results in recently deleted (cleared) log entries being stored in other (unrelated) *.evtx journ…

My DFIR Blog

My long post about wide-block & AEAD modes in full-disk encryption: it cover threat models, vulnerabilities, and edge cases.

Key points:
- It's common for FDE implementations to fail outside of the encryption layer.
- Wide-block modes don't protect against CWE-636 (Failing Open), which can lead to things like CVE-2025-4382.
- AEAD modes vs. code that doesn't handle read errors correctly: even FS drivers can misbehave (e.g., validation errors get suppressed and also lead to missing directory entries).
- Defusing the Elephant diffuser: injecting a bunch of null bytes into the BitLocker-encrypted volume (AES-CBC with Elephant diffuser). An interesting but unexploitable bug present since Vista.
- BestCrypt Volume Encryption breaks many XTS mode guarantees (and the vendor doesn't care).

https://dfir.ru/2025/05/08/disk-encryption-wide-block-modes-authentication-tags-arent-silver-bullets/

Disk encryption: wide-block modes, authentication tags aren’t silver bullets

Recently, IEEE released the P1619/D12 (October 2024) draft that changes the XTS mode of operation of the AES cipher. In particular, there is a new requirement: The total number of 128-bit blocks in…

My DFIR Blog

Unfortunately, this paper from 2017 is still relevant.

https://github.com/MotherOfAllVoids/bachelor_thesis/blob/master/text/flaw.pdf

1. BestCrypt Volume Encryption (BCVE) allows watermarking attacks.
2. BCVE allows plaintext injection attacks.
3. BCVE allows forced decryption of some sectors.

It doesn't matter that AES-XTS is used, the vulnerability is in the function wrapping encryption/decryption routines.

Jetico is aware of this flaw, but they won't fix it.

The first two attacks aren't relevant if your threat model excludes users mounting encrypted volumes after an adversary had access to them. This is not the same as physical access, because remote access to unmounted encrypted volumes is possible in dual-boot scenarios, etc.

The third attack allows adversaries to remotely force the decryption of some sectors (like those belonging to a database used by a web-facing application) through spraying (repeatedly causing the INSERT operation of) a specific 16-byte pattern.

Do we really need XTS key scopes here?

bachelor_thesis/text/flaw.pdf at master · MotherOfAllVoids/bachelor_thesis

This repo contains the results of my bachelor thesis at FIT CTU. The thesis was focused on reverse engineering and security analysis of BestCrypt Volume Encryption. I found several vulnerabilities ...

GitHub

Now that I think about it, perhaps it's a good thing that Trend Micro has foisted this ZDI-CAN-25373 nonsense upon us.

Sometimes it's good to have a nice litmus test to tell what parties in the infosec world are operating in purely self-serving and/or repost-without-understanding mode. 😂

My blog post and a PoC disk image are here: https://dfir.ru/2025/02/23/symlink-attacks-without-code-execution/
Symlink attacks without code execution

Background Let’s take a look at the following piece of code: if (is_infected_file(path)) { remove_file(path); } This is a oversimplified routine from a typical antivirus scanner — it takes a …

My DFIR Blog

According to Microsoft (MSRC), attacks involving symlinks stored on removable drives or in file system images (like VHDX) are not vulnerabilities.

If an unprivileged user manages to quickly replace a regular file in such a location with a symlink to another file (can point anywhere, even into the C:\Windows directory), this is okay.

This means that attackers can defeat existing symlink mitigations ("RedirectionTrust" plus "only privileged users can create symlinks to files") when they are capable of:

- attaching and mounting a removable drive (AV:P/PR:L), or

- mounting a VHDX image (AV:N/PR:N in the worst case, when a VHDX image is delivered via e-mail and then it gets double-clicked by a user, no code execution on the target machine required), or

- mounting a custom file-based container using disk encryption software like VeraCrypt (AV:L/PR:L, because anyone can mount a file-based container).

There is a small bonus: attackers win the race (against the program that follows symlinks when performing privileged operations) in almost every case, because the "replace a regular file with a symlink to another file" primitive comes from the NTFS driver, which performs "a more atomic" replace operation than any usermode application.

The secret is... This is about a crafted file system image, when the "\test\test.txt" file is opened/listed for the first three times (this number is attacker-controlled and can be tuned), it's a regular file; when this file is opened for the fourth time, it's a symlink (the actual replace is performed by the healing routines in the NTFS driver).

I'm attaching a screenshot demonstrating the "not-a-vulnerability".

Symlink attacks without code execution? Yes!