Security

Cyber Security, IT Security, Cyber Defence

Articles and presentations about Cyber Security

Here is a list of all articles and presentations I have published about Cyber Security so far.

Weaponized File Formats

This is a series of articles about file formats and related security issues. In 2003 I had presented an article in French about this subject at the SSTIC conference: [SSTIC03]. In the following articles I will provide an updated version in English with more information about common file formats.

VBA Macro analysis: Beware of the Shift Key!

Many malware analysts like to use the VB Editor in MS Word or Excel to analyze malicious macros, because it provides a nice debugging environment. It is a convenient solution to run VBA code in its native context, in order to unmask heavily obfuscated macros.

oletools - python tools to analyze OLE and MS Office files

python-oletools is a package of python tools to analyze Microsoft OLE2 files (also called Structured Storage, Compound File Binary Format or Compound Document File Format), such as Microsoft Office documents or Outlook messages, mainly for malware analysis, forensics and debugging. It is based on my olefile parser. 

Using VBA Emulation to Analyze Obfuscated Macros

ViperMonkey is an experimental toolkit that I have been developing since early 2015, to parse VBA macros and emulate their execution. This articles shows how it can be used to analyze obfuscated macros and extract hidden strings/IOCs.

Malware Search

This custom Google search engine helps you find malware samples containing specific strings, filenames, hashes or other IOCs. It uses the data indexed by several websites including malwr.com, hybrid-analysis.com, virustotal.com and virusshare.com.

For example, search "VB_Nam" to find malicious VBA macros, or "\objdata" to find RTF files with OLE Package objects.

 

How to detect most malicious macros without an antivirus

mraptor is a simple tool designed to detect malicious VBA macros in MS Office files, based on characteristics of the VBA code. This article explains how it works, and how it can be used in practice.

Anti-Analysis Tricks in Weaponized RTF

This article describes several anti-analysis tricks found in recent malicious RTF documents, and how I improved rtfobj to handle them.

8KB of malware crammed into a single command line in a macro

A few days ago, @Bry_Campbell told me about a strange sample with a malicious macro, that could not be fully analyzed with online sandboxes and the usual tools.

How to grill Malicious Macros - SSTIC15

Since 2014, malicious macros are coming back. And their success in recent campaigns demonstrates that it is still an effective way to deliver malware, sixteen years after Melissa.

This is a presentation that I gave to the SSTIC symposium in June 2015, translated to English. It explains what malicious macros can do, how their code can be obfuscated, and some of the anti-analysis tricks observed in recent cases. Then it shows several tools that can be used to analyze macros, including oledump and olevba.

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