Here is a list of all articles and presentations I have published about Cyber Security so far.
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.
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.
It is sometimes useful to look for malware samples containing a specific string. For example, you might look for samples sharing similar code to analyze a malware campaign with different targets. Another use case is discovering the original version of a modified file, as described in my article "Unmasking Malfunctioning Malicious Documents".
From time to time, people report strange malicious documents which are not successfully analyzed by malware analysis tools nor by sandboxes. Let's investigate. (this is a follow-up to the post "Malfunctioning Malware" by Didier Stevens)
olefile (formerly OleFileIO_PL) is a Python package to parse, read and write Microsoft OLE2 files (also called Structured Storage, Compound File Binary Format or Compound Document File Format), such as Microsoft Office 97-2003 documents, vbaProject.bin in MS Office 2007+ files, Image Composer and FlashPix files, Outlook MSG files, StickyNotes, several Microscopy file formats, McAfee antivirus quarantine files, etc.
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.
olevba is a script to parse OLE and OpenXML files such as MS Office documents (e.g. Word, Excel), to detect VBA Macros, extract their source code in clear text, decode malware obfuscation (Hex/Base64/StrReverse/Dridex) and detect security-related patterns such as auto-executable macros, suspicious VBA keywords used by malware, and potential IOCs (IP addresses, URLs, executable filenames, etc). It is part of the python-oletools package.
This article describes the Microsoft Office 97-2003 legacy/binary file formats (doc, xls, ppt), related security issues and useful resources.
This article presents several tools that can be used to extract VBA Macros source code from MS Office Documents, for malware analysis and forensics. It also provides an overview of how VBA Macros are stored.