Rascals are always sociable, and the chief sign that a man has any nobility in his character is the little pleasure he takes in others company. Arthur Schopenhauer

This blog posts serie discusses various means adversaries employ to deliver their malicious code using macro-enabled Office documents. We outline staged vs. stageless considerations and relevant VBA implementations to then delve into problem of concealing attacker’s intents in OpenXML structures. This article explores currently known and understood strategies, whereas in second part I’ll release my novel (at least as far as I’m concerned) technique for uniformly hiding malware in Word, Excel and PowerPoint in a storage that isn’t covered by open-source maldoc analysis tooling. Backdooring Office Structures. Part 1: The Oldschool