Windows on Insinuator.net - Bold Statements

Windows Hello for Business – Full Report Has Been Released

Thu, 16 Jul 2026 00:00:00 +0000

Yesterday, the BSI (the German Federal Office for Information Security, or Bundesamt für Sicherheit in der Informationstechnik in German) published the first result document from the “Windows dissected” (ger.: “Windows seziert”) project: our analysis of Windows Hello for Business (WHfB). If you have followed this blog over the past year, you have seen the pieces. The full 170-page report has now been published. And it can be downloaded from the project page.

Windows Early Boot Configuration: The CmControlVector and PspSystemMitigationOptions

Mon, 13 Apr 2026 00:00:00 +0000

While investigating how process mitigation settings are initialized, I encountered the global variable PspSystemMitigationOptions. Tracing how this value is populated led me to the CmControlVector. In this blog post, we take a look at the Windows kernel land configuration manager, especially its global CmControlVector variable. Quick note: the kernel’s configuration manager is not related to Microsoft Intune’s Configuration Manager. In short, the configuration manager is responsible for managing and implementing the registry. However, it is also responsible for setting up parts of the system during early boot.

Release of ERNW White Paper 73: Analyzing WinpMem Driver Vulnerabilities

Thu, 02 Oct 2025 00:00:00 +0000

Today we are releasing a new white paper that delivers a technical analysis of security weaknesses discovered in WinpMem, an open-source Windows memory acquisition driver widely used in digital forensics.

After a concise primer on relevant Windows internals (virtual vs. physical memory, page tables and PTEs, CR3 context switching, and kernel and user memory separation), the report examines how both the fundamental design of WinpMem and specific implementation choices create severe risk.

Windows Hello for Business - Faceplant: Planting Biometric Templates

Fri, 29 Aug 2025 00:00:00 +0000

We are back from Black Hat USA, where we presented our research on Windows Hello for Business (Slides) once more. In the last two blog posts, we have discussed the architecture of WHfB and past attacks, as well as how the database works and how to swap identities in the database.

First, a few words regarding my experience at Black Hat: for me, it was the first time attending the conference and then directly as a speaker. I thoroughly enjoyed Black Hat. It took a while to get used to the size of the conference and the vibe of Las Vegas. What was especially interesting for me was connecting with other researchers. One thing that stood out was meeting with the team from MSRC and putting faces to the team itself. It feels way more personal to know who you’re talking to when you know the people handling your cases. During TROOPERS I typically have the chance to connect with many researchers, mainly from Europe. At Black Hat US, on the other hand, it is possible to connect more with the US scene and meet people you haven’t seen in a long time! Seeing familiar faces again is always nice, as opposed to putting them into your biometric template database. One nice detail was that some international researchers are aware of the research BSI (German: “Bundesamt für Sicherheit in der Informationstechnik” – “German federal office for IT security”) is facilitating. The results of our presentation stem from the “Windows Dissected” project we are performing on behalf of the BSI.

Windows Hello for Business - The Face Swap

Tue, 15 Jul 2025 00:00:00 +0000

In the last blog post, we discussed the full authentication flow using Windows Hello for Business (WHfB) with face recognition to authenticate against an Active Directory with Kerberos and showcased existing and new vulnerabilities. In this blog post, we dive into the architectural challenges WHfB faces and explore how we can exploit them.

The majority of the work was conducted in the context of the “Windows Dissected” project. This project, funded by the BSI (German: “Bundesamt für Sicherheit in der Informationstechnik” – the German Federal Office for Information Security), has the goal to perform ” various in-depth security analyses of security-critical components and functions in Windows.” Over the next years we will discuss these results here once they are published.

Windows Hello for Business – Past and Present Attacks

Fri, 20 Jun 2025 00:00:00 +0000

Windows Hello for Business is a key component of Microsoft’s passwordless authentication strategy. It enables user authentication not only during system sign-in but also in conjunction with new and advanced features such as Personal Data Encryption, Administrator Protection, and Recall. Rather than depending on traditional passwords, Windows Hello leverages a PIN or biometric methods – such as fingerprint or facial recognition – to unlock cryptographic keys protected by the Trusted Platform Module (TPM).

Jigsaw RDPuzzle: Piecing Attacker Actions Together

Wed, 29 Jan 2025 00:00:00 +0000

In a recent incident response project, we had the chance to virtually look over the attackers’ shoulder and observe their activities. The attackers used the Remote Desktop Protocol (RDP) for lateral movement within the compromized environment and beyond (MITRE techniques T1570, T1021). As a matter of fact, RDP creates cache files that contain tiles of the transferred screen recording data. While this fact is well-known and there are existing tools, we found it worth reporting because of two different aspects:

CrowdStrike: What is the worldwide BSOD all about?

Tue, 20 Aug 2024 00:00:00 +0000

This article is about the massive BSOD triggered by CrowdStrike worldwide on July 19. Analysis and information from CrowdStrike or other sources are regularly published, completing what is expressed here. Updates may also be provided in the future.

Friday, July 19, is a day to be remembered in computing history as the day of one of the biggest BSODs (Blue Screens of Death). We have seen air traffic come to a standstill over the USA and people climbing ladders with USB sticks to update giant screens. The impact was still measurable over many days. The question on everyone’s lips is how that all happened. CrowdStrike provided, on a regular basis, an explanation for people to understand what happened. But explanations can be hard to understand, especially for one who would like to read directly within CrowdStrike’s internal wording in their publications and regarding technical driver implementation details. Also, the analysis misses some points we consider relevant for secure software development. This article discusses conclusions from this massive crash, especially the necessity to change our mindset about software. This means we should understand, document, and evaluate independently software provided by vendors to know exactly what we install on our systems and to figure out the risk that may be taken by using the software. The time of naive belief in software magic must end with a third party’s independent review of the software, analysing its reliability, security, and stability. This is an activity we have been doing at ERNW for years, especially for e.g. the German Federal Office for Information Security (BSI)¹.

BSI Publishes Windows 10 SiSyPHuS Reports: Application Compatibility Infrastructure, Microsoft Defender Antivirus ETW Usage and Device Setup Manager Service

Tue, 16 Apr 2024 00:00:00 +0000

The German Federal Office for Information Security (BSI – Bundesamt für Sicherheit in der Informationstechnik) has published several papers ERNW created as part of the long-term SiSyPHuS Win10-Project. This project focuses on system analysis of selected parts of the Windows 10 operating system performed by ERNW.

Analysis of the Application Compatibility Infrastructure (ACI): In this work we present an overview of the ACI technology along with a technical analysis of the compatibility protocol which is used first to determine if a compatibility solution needs to be applied, and second, to apply said compatibility solution. Furthermore, threats and mitigation in the context of the technology are presented a long with a monitoring approach. Finally, configuration and logging capabilities are discussed.

Release of PTE Analysis plugins for Volatility 3

Fri, 31 Dec 2021 00:00:00 +0000

I’m happy to announce the release of several plugins for Volatility 3 that allow you to dig deeper into the memory analysis. One of those plugins is PteMalfind, which is essentially an improved version of malfind. Another one is PteResolve which, similarly to the WinDBG command !pte, allows you to inspect Page Table Entry (PTE) information for e.g., a given virtual address. In this blog post we will have a closer look at these and more plugins, and the PteEnumerator base class and what you can do with it. The memory dump used for this blog post is available here. Some of the injection tools used in this blog post can be gathered from here.

Microsoft Office Telemetry: Report Release

Tue, 17 Nov 2020 00:00:00 +0000

The German Federal Office for Information Security (orig., ger., Bundesamt für Sicherheit in der Informationstechnik – BSI) has published our report on Microsoft Office Telemetry.

Microsoft has released a set of privacy settings for Office, one of which enables users to configure the type and amount of diagnostic (i.e., telemetry) data that Office may send to Microsoft. When deployed, it is available in the form of a group policy setting. It allows users to configure one of the following diagnostic data levels: required, optional, or neither. The report we produced:

Windows Insight: The Windows Telemetry ETW Monitor

Tue, 14 Jan 2020 00:00:00 +0000

The Windows Insight repository now hosts the Windows Telemetry ETW Monitor framework. The framework monitors and reports on Windows Telemetry ETW (Event Tracing for Windows) activities – ETW activities for providing data to Windows Telemetry. It consists of two components:

the Windbg Framework: a set of scripts for monitoring Windows Telemetry ETW activities. The scripts are fed to a running windbg instance, connected to the Windows instance whose Windows Telemetry ETW activities are monitored.
the Telemetry Information Visualization (TIV) framework for visualization of information and statistics. The TIV framework is a set of Python scripts that visualize information and statistics based on the data produced by the Windbg Framework. The output of the TIV framework is a report in the form of a web page.

TROOPERS20 Training Teaser: Insight Into Windows Internals

Mon, 25 Nov 2019 00:00:00 +0000

Windows 10 is one of the most commonly deployed operating systems at this time. Knowledge about its components and internal working principles is highly beneficial. Among other things, such a knowledge enables:

in-depth studies of undocumented, or poorly documented, system functionalities;
development of performant and compatible software to monitor or extend the activities of the operating system itself; and
analysis of security-related issues, such as persistent malware.

The “Insight into Windows Internals” training offered at TROOPERS20 delivers knowledge on the core components and inner working principles of Windows 10. For example, the training provides knowledge on how Windows 10 uses virtualization to isolate security-critical functionalities from attackers that have managed to compromise the system. The training includes a variety of practical exercises allowing attendees to observe first-hand the operation of Windows 10.

Windows Insight: Code integrity and WDAC

Wed, 30 Oct 2019 00:00:00 +0000

The Windows Insight repository now hosts three articles on Windows code integrity and WDAC (Windows Defender Application Control):

Device Guard Image Integrity: Architecture Overview (Aleksandar Milenkoski, Dominik Phillips): In this work, we present the high-level architecture of the code integrity mechanism implemented as part of Windows 10.
Windows Defender Application Control: Initialization (Dominik Phillips, Aleksandar Milenkoski): This work describes the process for initializing WDAC performed by the Windows loader and the kernel when Windows 10 is booted.
Windows Defender Application Control: Image verification (Aleksandar Milenkoski): This work discusses the workflow of WDAC for verifying images.

– Aleksandar Milenkoski

Windows Insight: Virtual Secure Mode

Wed, 12 Jun 2019 00:00:00 +0000

The Windows Insight repository currently hosts four articles on VSM (Virtual Secure Mode):

Virtual Secure Mode: Architecture Overview (Aleksandar Milenkoski): In this work, we discuss the architecture of a virtualized Windows environment.
**Virtual Secure Mode: Communication Interfaces **(Aleksandar Milenkoski): In this work, we discuss the communication interfaces that VSM implements: Isolated User Mode (IUM) system calls, normal-mode services, secure services, and hypercalls.
Virtual Secure Mode: Protections of Communication Interfaces (Aleksandar Milenkoski): This work discusses implemented mechanisms for securing the above VSM communication interfaces. This includes restrictions on issuing hypercalls, data marshalling and sanitization, and secure data sharing.
Virtual Secure Mode: Initialization (Dominik Phillips, Aleksandar Milenkoski): This work describes the process for VSM initialization activities performed by the Windows loader and the Windows kernel when Windows 10 is booted.

– Aleksandar Milenkoski

Windows Insight: The TPM

Mon, 27 May 2019 00:00:00 +0000

The Windows Insight repository currently hosts three articles on the TPM (Trusted Platform Module):

The TPM: Communication Interfaces (Aleksandar Milenkoski): In this work, we discuss how the different components of the Windows 10 operating system deployed in user-land and in kernel-land, use the TPM. We focus on the communication interfaces between Windows 10 and the TPM. In addition, we discuss the construction of TPM usage profiles, that is, information on system entities communicating with the TPM as well as on communication patterns and frequencies;
The TPM: Integrity Measurement (Aleksandar Milenkoski): In this work, we discuss the integrity measurement mechanism of Windows 10 and the role that the TPM plays
as part of it. This mechanism, among other things, implements the production of measurement data. This involves calculation of hashes of relevant executable files or of code sequences at every system startup. It also involves the storage of these hashes and relevant related data in log files for later analysis;

Windows Insight: A New ERNW Repository

Thu, 23 May 2019 00:00:00 +0000

We are glad to announce the Windows Insight repository. The content of this repository aims to assist efforts on analysing inner working principles, functionalities, and properties of the Microsoft Windows operating system. This repository stores relevant documentation as well as executable files needed for conducting analysis studies.

Some of the content of this repository has been created in the course of a project named ‘Studie zu Systemaufbau, Protokollierung, Härtung und Sicherheitsfunktionen in Windows 10 (SiSyPHuS Win10)’ (ger.) – ‘Study of system design, logging, hardening, and security functions in Windows 10’ (eng.). This project has been contracted by the German Federal Office for Information Security (ger., Bundesamt für Sicherheit in der Informationstechnik – BSI). The work planned as part of the project is conducted by ERNW GmbH, starting in May 2017.

Troopers & Chill…

Fri, 26 Apr 2019 00:00:00 +0000

As promised in my previous post, I am back for an overview of the Troopers19 – Active Directory related talks… Videos have been published and it’s popcorn time… So if you are into stories about Kingdoms and Crown Jewels, grab your loved one [or a drink…] and turn the lights down low, ’cause tonight it’s “Troopers & Chill…”

Warning: Don’t watch it all in one go… or you will start to feel some anxiety and pain…
and then the Flying Dutchman will move to the cloud… And at that point we are not insured anymore.

TROOPERS19 Training Teaser: Insight Into Windows Internals

Tue, 15 Jan 2019 00:00:00 +0000

in-depth studies of undocumented, or poorly documented, system functionalities;
development of performant and compatible software to monitor or extend the activities of the operating system itself; and
analysis of security-related issues, such as persistent malware.

The “Insight into Windows Internals” training offered at TROOPERS’19 delivers knowledge on the core components and inner working principles of Windows 10. For example, the training provides knowledge on how Windows 10 uses virtualization to isolate security-critical functionalities from attackers that have managed to compromise the system. The training includes a variety of practical exercises allowing attendees to observe first-hand the operation of Windows 10.

The Dog Whisperer’s Handbook

Mon, 19 Nov 2018 00:00:00 +0000

Generally speaking, I’m more of a Cat type of guy, but I have to say I really love BloodHound. And if you do too, you are in for a treat…
Last week, the ERNW Insight Active Directory Security Summit took place in Heidelberg. (More Info)
For this occasion, @Enno_Insinuator asked me if I would like to deliver a BloodHound Workshop, and of course I accepted the challenge…

We had a full class, I had a blast training it, and I hope the trainees enjoyed it as much as I did.
But that’s not all…
Another part of the deal was that I had to write a Training Guide that we would then share with the Community (aka you).
So here it is, fresh from the Heidelberg press and available for download:

#TR18 Defense & Management Summaries

Fri, 23 Mar 2018 00:00:00 +0000

This blogpost contains summaries of talks from this year’s TROOPERS18 Defense & Management Track.

All Your Cloud Are Belong to Us

The talk “All Your Cloud Belong Are Belong to Us” was held by Nate Warfield, who is a Senior Security Program Manager for the Microsoft Security Response Center (MSRC).
Before Microsoft he worked as a network engineer about 18 years and 10 of this for a large amount of cell phone companies.
Nate gives an overview about the state of the cloud solution provided by Microsoft, Azure, and how he hunts vulnerabilities in this environment.
Finally he concludes that the giving up your infrastructure to the cloud doesn’t mean that you give up your responsibility.

Creating Static Binaries for Nmap, Socat and other Tools

Fri, 23 Feb 2018 00:00:00 +0000

In various scenarios it might be helpful or even required to have a statically compiled version of Nmap available. This applies to e.g. scenarios where only limited user privileges are available and installing anything to the system might not be desirable.

For such cases I’ve started to create recipes to build such binaries. Similar projects are already available on GitHub, but there are several reasons why I chose to create my own tools:

White Paper on Multi-Factor Authentication in Microsoft Windows Environments

Mon, 29 Jan 2018 00:00:00 +0000

A new ERNW whitepaper was just published. I wrote this whitepaper in the course of my bachelor thesis and it examines multi-factor authentication in Microsoft Windows environments:

Credential theft and the subsequent reuse of stolen credentials are a significant problem in today’s information security. To counter the associated risks, a planned approach is required as part of a comprehensive security architecture program. This includes the implementation of multi-factor authentication as an important building block. This whitepaper covers the relevant steps of implementing a multi-factor authentication system in an enterprise environment and closes with a security evaluation.

IPv6 Properties of Windows Server 2016 / Windows 10

Mon, 30 Jan 2017 00:00:00 +0000

In this post we’ll take a detailed look at the properties of the Windows Server 2016 IPv6 stack.
I perform(ed) this exercise for several reasons:

Server 2016 is the latest OS released by Microsoft so this might give an indication as for their plans & strategy when it comes to supporting certain specifications.
(here you may keep in mind that the ~50 IETF meetings having passed since the publication of RFC 2460 provided ample opportunity for creative minds to come up with ever new ideas for “enhancing” IPv6, without too much real-life feedback/reality checks from enterprise space though, as simply not many of such organizations have deployed it at scale… or are incentivized to send their employees to week-long meetings in expensive hotels on other continents twice a year…).
as I laid out in this post the configuration approach an organization takes for their servers might depend on the support of specific features.
obviously for both IPv6 planning and operations it might be helpful to understand the respective behavior of individual operating systems (which is why we researched stuff like this or this in the past).
many years ago Microsoft published white papers with details as for the TCP/IP parameters of their OSs (incl. stuff like registry parameters to control it etc.) but I’m not aware of such a document for Server 2016 or Windows 10. I hence hope this post can somewhat contribute to public knowledge of the intricacies of their latest IPv6 stack.

Version

Diving into EMET

Mon, 26 Sep 2016 00:00:00 +0000

Last week, we decided to take a look onto the EMET library provided by Microsoft. This library is intended to introduce several security features to applications which are not explicitly compiled to use them.

It also adds an additional layer to protect against typical exploiting techniques by filtering library calls, preventing usage of dangerous functions/components and inserting mitigation technologies.

As EMET is already a target for many researchers, we currently only started to get an overview of it’s structure and how the different components are interacting with each other. Today we would like to share some of our results with you.

PFX Profiles in Microsoft’s System Management Server

Fri, 05 Aug 2016 00:00:00 +0000

In a recent assessment, we had to evaluate how Microsoft’s System Management Server (SMS) certificate management solution (CMS) stores and handles certificates. This question came up because sensitive, encrypted user certificates were to be stored in the SMS CMS. Due to the sensitivity of the handled certificates, we assessed the protection capabilities of the certificate management solution against extraction attempts from a local attacker with administrative privileges.

How did we do it?

We determined a five steps approach to gain access to the certificates and be able to decrypt the accessed certificate material:

Your Mouse Got Sick and You Don’t Know it. aka “Reverse Shell via Mouse”

Fri, 29 Jul 2016 00:00:00 +0000

Ever got a backdoor installed on your computer by your beloved mouse? Here’s the story of a poor mouse that got really, really sick.

Agent “Danger Mouse”

Do you remember the times where people put Teensy-boards and USB hubs in their mouses? [Chris? ;)] Their aim was to attach an additional Human Interface Device (HID, like keyboards or mouses) with some payload in kind of e.g. keystrokes or mouse movements. Also, there are devices available like the USB Rubber Ducky in the housing of a USB thumb drive.
The principle is easy: The tools are using a programmable microcontroller with the capability to emulate USB HID. That’s it. Just program your board of choice with the payload fitting your needs and plug it in at the target computer. The latter will recognize it as a keyboard/mouse and the payload-keystrokes will be entered.
But why should external hardware be used? Many modern gaming peripherals provide functions to store macros on them, including enough onboard memory for little payloads.

How ‘security’ black boxes might corrupt your investment

Fri, 29 Apr 2016 00:00:00 +0000

Usually I’m not the kind of guy who talks about such economic topics. Because I’m an engineer / security researcher who is exclusively concerned with understanding technical problems and if possible, solving them accordingly. My whole education is based on this and contains predominantly technical aspects of information security. This sometimes makes it difficult to understand what the market cares about (and why some products are being developed / exist on the market 😉 ). Nevertheless, a current engagement for one of our customers made me stumble upon such a product.

Security Assessment of Microsoft DirectAccess

Wed, 06 Apr 2016 00:00:00 +0000

A talk about DirectAccess (an IPv6-only VPN solution) was given by our colleague Ali Hardudi during IPv6 summit. Ali has recently finished his master thesis on this topic.

The DirectAccess VPN technology was introduced by Microsoft starting from Windows server 2008. It allows users remotely, seamlessly and securely connect to their internal network resources without a need to provide user credentials, which is done using different technologies such as Windows domain group policies.

I Have the Power(View): Offensive Active Directory with PowerShell

Thu, 31 Mar 2016 00:00:00 +0000

In his talk I have the Power(View): Offensive Active Directory with PowerShell Will Schroeder, a researcher and Red teamer in Veris Group´s Adaptive Thread Division, presented offensive Active Directory information gathering technics using his Tool PowerView.

PowerView does not use the built in AD cmdlets to be independent from the Remote Server Administration Tools (RSAT)-AD PowerShell Module which is only compatible with PowerShell 3.0+ and by default only installed on servers that have Active Directory services roles. PowerView, however, is compatible with PowerShell 2.0 and has no outer dependencies. Furthermore, it does not require any installation process.

The Joy of Sandbox Mitigations

Mon, 28 Mar 2016 00:00:00 +0000

This year at TROOPERS16 in Heidelberg we welcomed James Forshaw for his talk about “The Joy of Sandbox Mitigations“.

He is a security researcher in Google’s Project Zero. He has been involved with computer hardware and software security for over 10 years looking at a range of different platforms and applications. With a great interest in logical vulnerabilities he has numerous disclosures in a wide range of products from web browsers to virtual machine breakouts as well as being a Pwn2Own and Microsoft Mitigation Bypass bounty winner. He has spoken at a number of security conferences including Black Hat USA, CanSecWest, Bluehat, HITB, and Infiltrate.

TROOPERS16 Training Teaser: Dos and Don’ts of Secure Active Directory Administration

Wed, 27 Jan 2016 00:00:00 +0000

In the last few years, attack techniques which fall in the categories of “Credential Theft” or “Credential Reuse” have grown into one of the biggest threats to Microsoft Windows environments. Microsoft has stated more than one time, that nearly almost all of their customers that run Active Directory have experienced “Pass-the-Hash” (PtH) attacks recently.[1] Once an attacker gains an initial foothold on a single system in the environment it takes often less than 48 hours until the entire Active Directory infrastructure is compromised. To defend against this kind of attacks, a well-planned approach is required as part of a comprehensive security architecture and operations program. As breach has to be assumed[2], this includes a preventative mitigating control strategy, where technical and organizational controls are implemented, as well as preparations against insider attacks. This is mainly achieved by partitioning the credential flow in order to firstly limit their exposure and secondly limit their usefulness if an attacker was able to get them. Although we spoke last year at Troopers 15 about “How to Efficiently Protect Active Directory from Credential Theft & Large Scale Compromise”[3], we would like to summarize exemplary later in this post Active Directory pentest findings that we classified in four categories in order to better understand what goes typically wrong and thus has to be addressed. For a better understanding of the overall security goals, we classified the findings as to belonging as a security best practice violation of the following categories:

Investigating Memory Analysis Tools – SSDT Hooking via Pointer Replacement

Sun, 13 Dec 2015 00:00:00 +0000

In this blogpost we will briefly explain a well known Syscall hooking technique (a more detailed explanation can be gathered from e.g. http://resources.infosecinstitute.com/hooking-system-service-dispatch-table-ssdt/) used by multiple malware samples (like the laqma trojan) and right after discuss how some memory analysis tools have trouble in the analysis and/or reporting of these.

Before we go further, I just shortly wanted to say, that this post is not intended to be a bashing of any tool. We have the greatest respect for all the effort and work which has been and most probably will be done in the future.

Black Hat Talks & Papers related to Windows/Active Directory Security

Fri, 07 Aug 2015 00:00:00 +0000

This year’s Black Hat US saw a number of quite interesting talks in the context of Windows or Active Directory Security. For those of you too lazy to search for themselves 😉 and for our own Windows/AD Sec team (who couldn’t send anyone to Vegas due to heavy project load) I’ve compiled a little list of those.

Paul Stone & Alex Chapman: WSUSPect – Compromising the Windows Enterprise via Windows Update
Slides here.
Whitepaper here. (Attention: on the BH website there’s an older this. the above link leads to the latest one).

How to go ahead with future end of life Windows (2003) Servers

Thu, 12 Feb 2015 00:00:00 +0000

Server operating systems with an OS, for which vendor support has ended, come with many risks that have to be considered and addressed. The primary goal should be always to decommission or migrate the majority of end-of-life (EoL) servers to OS versions, supported by the vendor. Here it should be noted that a migration to an up-to-date OS should be preferably done before your organization enters the end of life of that software 😉

Skeleton Key – a Nasty Piece of Malware. Some Remarks.

Thu, 15 Jan 2015 00:00:00 +0000

Just recently, Dell SecureWorks Counter Threat Unit(TM) (CTU) researchers published details (see http://www.secureworks.com/cyber-threat-intelligence/threats/skeleton-key-malware-analysis/ ) on a especially nasty piece of malware that bypasses authentication on Active Directory (AD) systems which implement single-factor (password only) authentication. Once deployed the malware stays quite noiseless in the Domain Controller´s (DC) RAM, and the DC´s replication issues caused by it weren´t interpreted – in this case – during months as a hint for system compromise. Probably the malware´s modification on the LSASS process reduced the DC´s ability to perform DC-to-DC authentication, but this is only speculation and not where we would like to go today.

IPv6 Hardening Guide for Windows Servers

Mon, 22 Dec 2014 00:00:00 +0000

After we recently released the “Linux IPv6 Hardening Guide” we got a number of suggestions “could you pls provide a similar document for $OS?” (btw: thanks to you all for the overwhelming interest in the Linux document and the active discussion of ip6tables rule approaches on the ipv6hackers mailing list).

Hence Antonios thankfully decided to put together a list of configuration steps for Windows servers. It can be found here.

Once more we’d like to emphasize that the approach described is only suited for very specific environments with high security requirements and an associated ratio of “generous operational resources”. From our perspective this guide is intended mostly to serve as a source of inspiration (“what could be done”) and for documentation purposes (“how to do it”). Everything described should be carefully tested in your specific environment.
For example, we were recently involved in IPv6 security planning in an organization where the Windows guys (completely legitimately) came up with a stance of “before we fully accept and ratify the strategy and policy just discussed, we’d like to get feedback from Microsoft, if we still have full support once we follow this path”.

Some Things to Consider when Using EMET

Fri, 08 Aug 2014 00:00:00 +0000

In the light of the recent release of version 5.0 of Microsoft’s Enhanced Mitigation Experience Toolkit (EMET) on July 31, it seems to be more than appropriate to talk a bit about the new features and some general things to take into account when using EMET (for the new certificate pinning feature of EMET 4.0, see Friedwart’s comment). For all of you who don’t know EMET, in short, it’s a free mitigation tool for Windows developed by Microsoft, helping the user by preventing vulnerabilities in software from being successfully exploited. The tool works by protecting applications via a number of security mitigation technologies, vastly extending Windows operating system mitigation capabilities as Data Execution Prevention (DEP) and Address Space Layout Randomization (ASLR).

Skype GPO

Thu, 03 Jul 2014 00:00:00 +0000

Hi all,

regularly we get requests from customers where the idea of using Skype as a VoIP solution in their corporate environment is brought up. There are a lot of eavesdropping and more conceptual concerns (e.g. refer to this or this, and of course the legendary “Silver Needle in the Skype” paper from Black Hat EU 2006), but those won’t be covered in this post (just to say this: at ERNW the use of Skype is strictly prohibited at by policy).

Microsoft Windows Update over IPv6 (or not?)

Wed, 21 May 2014 00:00:00 +0000

Hello everyone,

I recently stumbled over a document from Microsoft which lists all services/applications that support IPv6. Most of the content wasn’t new for me, but one item caught my attention. Windows Update. I haven’t heard before that Windows Update can be done over IPv6 (but this could just be me not looking hard enough ;)), so I was eager to test it out seeing if this is really the case. I was also curious why Microsoft referenced this document in the respective column.

The Role of VGX.DLL in the Context of the Latest IE 0-Day

Tue, 13 May 2014 00:00:00 +0000

On Saturday, April 26 Microsoft announced that Internet Explorer version 6 until version 11 is under potential risk against drive-by attacks from malicious websites, regardless of the underlying Microsoft operating system and the associated memory protection features integrated with the operating system. Microsoft has assigned CVE-2014-1776 to this unknown use-after-free vulnerability, which in the worst case could allow remote code execution if a user views a specially crafted website. If an attacker successfully exploits this vulnerability, s/he will gain the same rights and privileges as the current user (once again, activated User Account Control [UAC] helps keeping privileges of the user low).

EMET v4.0 with New Certificate Trust Feature Released

Mon, 01 Jul 2013 00:00:00 +0000

Microsoft released EMET v4.0 with a new (security) feature that enables protection against fraudulent websites or compromised root certification authorities (do you remember Comodo, DigiNotar, DigiCert, Turktrust et al. ;-)?)

EMET defines via “certificate trust“ a trust chain between the domain name of a website (and its associated website certificate) and a root CA certificate. This is done through so called “pinning rules”. Here is one of the default pinning rules of EMET 4.0 for the domain name login.live.com:

Loki for Windows released

Thu, 08 Nov 2012 00:00:00 +0000

Today is a great day, its the day, Loki finally runs on all big operating systems. Im proud to announce the first Loki release for Windows!

There are a few things not working (yet / at all) under Windows. Those are:

The WLCCP Module – ive not yet managed to build and link against asleap on windows [but time may help (-; ]
TCP-MD5 Auth for BGP – This will never work, as Windows has no TCP-MD5 impl. in the kernel
The MPLS Module – Had some hassle here with WinPcap, may be working in the future

The most testing so far was done on Windows 7 were all the other functions work as they do on Linux and Mac.

Microsoft Advisory 2757760: Windows Internet Explorer Zero-Day Vulnerability

Wed, 19 Sep 2012 00:00:00 +0000

Actually a Windows Vulnerability (Microsoft Advisory 2757760) related to the Internet Explorer Version 7, 8 and 9 is in the news. Microsoft is aware of the problem, but there’s no patch available yet. We call this a 0-Day :-). Making the problem even worse, on monday reliable exploit code was released within the Metasploit project, so exploit code is already in the wild.

Basically Microsoft suggests two workarounds:

Usage of EMET (Enhanced Mitigation Experience Toolkit)
Disabling Active X and Active Scripting in the Internet Settings

But both of them have some impact: EMET must be deployed before any usage (btw. EMET can be configured via Group Policies) and disabling Active X and Active Scripting might break some business relevant web sites (that can be added to the “Trusted Sites” Zone, but might produce major operational effort).

MS10-063, Prevention

Wed, 15 Sep 2010 00:00:00 +0000

One of the four vulnerabilities rated “critical” from yesterday’s MS patchday, that is MS10-063, has an interesting “Workarounds” section as for MS Internet Explorer. There it’s stated:

“Disabling the support for the parsing of embedded fonts in Internet Explorer prevents this application from being used as an attack vector.”

which, according to the advisory, should/can be done by setting the “Font Downloading” parameter to “Disable”.

Which is exactly what this document suggests. So taking a preventive approach, once more, might have saved some concerns (“Will we be targeted by this one”) and patch/testing time…