Bugging Microsoft Files: Part 2 – Xlsx Files using Microsoft Excel
Summary
This article details a method for embedding tracking bugs within native .xlsx files using Microsoft Excel. It follows up on a previous post and provides technical instructions for achieving this.
IFF Assessment
FOE
The article describes a technique that could be used by attackers to track recipients of malicious Excel files, which is detrimental to defenders.
Defender Context
Defenders should be aware of novel methods for embedding tracking or malicious payloads within seemingly innocuous document formats like Excel. This highlights the need for robust email and endpoint security solutions that can inspect document contents for suspicious artifacts, and for user education on safe handling of attachments.