Malware Analysis Exercise – Living Off the Land with Powershell

It is common for threat actors to utilize living off the land (LOTL) techniques, such as the execution of PowerShell to further their attacks and transition from macro code. This lab is intended to show how you can often times perform quick analysis to extract important IOCs. While there may be several ways to answer these questions the focus on this exercise is on static techniques for analysis. You can find the exercise, artifacts and full walk-through on my Github at https://github.com/jstrosch/malware-samples/tree/master/malware_analysis_exercises/2020/December Looking for more of a challenge? Try this on CyberDefenders as part of their CTF! https://cyberdefenders.org/labs/51

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Malware Analysis Exercise – Getting Started with Excel 4 Macros

Recently, we have seen a resurgence of Excel-based malicious office documents. However, instead of using VBA-style macros, they are using older style Excel 4 macros. This changes our approach to analyzing these documents, requiring a slightly different set of tools. In this challenge, you’ll get hands-on with two documents that use Excel 4.0 macros to perform anti-analysis and download the next stage of the attack. You can find the exercise, artifacts and full walk-through on my Github at https://github.com/jstrosch/malware-samples/tree/master/malware_analysis_exercises/2021/February. Looking for more of a challenge? Try this on CyberDefenders as part of their CTF! https://cyberdefenders.org/labs/55

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How-To: Installing Oledump in Windows

In this video, we’ll look into installing OLEDUMP in Microsoft Windows. Microsoft office documents are a common vehicle used by malware authors to deliver malware. These documents, used for malicious purposes, are commonly referred to as maldocs. While there has been a variety of ways in which they have been used, one of the more prevalent is through the use of macros. Macros are written in Visual Basic for Applications (VBA), which is well documented on the Microsoft Developer Network (MSDN). This API allows malware authors to hook into life-cycle events of a document, such as AutoOpen, AutoClose and AutoExit…

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Maldoc Workshop at Hack-in-the-Box CyberWeek (UAE)

I gave a free 4-hour workshop as part of the Hack-in-the-Box (HITB) CyberWeek (November 15th, 2020). The focus of this workshop was on analyzing malicious Word and Excel documents: Malicious office documents continue to be an effective tool for threat actors to compromise their victims and gain access to an organization’s network. While these documents have been around for a while, malware authors continue to find effective ways of abusing functionality to minimize their detection. This year alone we have seen a resurgence of such techniques through the use of Excel 4 Macros and other creative ways to bypass detection….

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Excel 4 Macros – Get.Workspace Reference

With the recent resurgence of the use of Excel 4 macros in malicious excel documents, I’ve found myself scouring the internet looking for language references. One such function that was particularly difficult to find documentation for was Get.Workspace, which takes a integer value as an argument and returns information about the environment. Since it appears that it is all but impossible to find Excel 4 macro documentation from Microsoft, I thought I’d create a few posts in the hopes of the content getting indexed and thus easier to find. The source of this information came from this PDF, which used…

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