Chapter 7: What has Microsoft changed about Office macros?

Discovering Microsoft’s evolving approach to Office Macros:

In early 2023, Microsoft unveiled significant changes to its policies concerning Office macros, demonstrating a proactive stance towards bolstering security measures. One notable change revolves around the default macro disabling policy for files originating from the Internet.

Going forward, macros will be blocked by default in all documents downloaded from the web. This means that users will no longer have the option to enable macro content with a simple click; instead,
blocking will be the default behavior.

Microsoft’s shift towards a more cautious approach reflects their commitment to safeguarding users against potential macro-based threats. The decision to block macros by default emphasizes the importance of factors such as the file’s source, Trusted Locations, Trusted Documents, and the Sender’s digital signature. These elements play a crucial role in determining whether macros within downloaded documents will be allowed to execute.

Decoding the Mark of the Web: Microsoft’s Shield Against Macro-Infected Office Documents

To grasp Microsoft’s protection mechanism against macro-infected office documents, it is crucial to delve into the concept of the Mark of the Web (MotW). This attribute plays a pivotal role in understanding how the process unfolds and safeguards users in the ever-evolving threat landscape.

The Mark of the Web is an attribute that accompanies any file downloaded from the Internet and is compatible with the NTFS file system. When a file is downloaded, it possesses an alternate data stream that contains vital information, including the Zone Identifier. Most users may already be familiar with this aspect, as modern browsers automatically add the zone information when files are downloaded to an NTFS system.

Source: Microsoft

The Zone Identifier signifies the source or zone of the file and determines its behavior within the system. The zones include the Internet, restricted zone, local machine, intranet, and trusted zone. Each zone enforces distinct protocols and controls over the file, influencing how the system accesses and interacts with it.

A closer look: Microsoft’s Interface Changes for Office Macros

Let’s take a closer look at how recent changes in Microsoft’s approach have transformed the end user’s perspective on enabling macro content. By examining the previous version, you can see that users could easily enable macro execution with a simple click. The warning message displayed at the top, highlighted in yellow, even provided a convenient button to facilitate this action.

However, in the current version, enabling macros has become more challenging for users. They now need to navigate through a different application to authorize macro execution. This shift presents a significant test for Microsoft, which was one of the reasons of the long-standing presence of macro malware.

Old vs new: How the security warning to enable macros looks on the end user screens

After receiving immediate feedback and acknowledging the complexities involved, Microsoft initially rolled back the update. But eventually, they successfully resumed the rollout of the VBA macro auto-blocking feature. This milestone marks a significant step forward in enhancing the security of Office documents.

While it’s important to note that this change doesn’t guarantee complete safety, it undoubtedly contributes to a safer environment for both security practitioners and end users.

Let us now continue our journey by exploring the impact this change had on the threat landscape.