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Macros and Malware – A Brief Overview

by Brett M. Christensen

Criminals use many and varied methods to distribute malware. One such method that has become increasingly common in recent years is to use malicious macros.

So, what Is a ‘Macro’ Anyway?

A macro is a set of commands and instructions that can be grouped as a single command in order to quickly and automatically accomplish a task.

Microsoft Office macros are made using the computer programming language Visual Basic for Applications (VBA). You can think of them as tiny computer programs that can be built to complete particular tasks.

Macros can be very helpful in some workflows and can be quite complex. But,  complex macros can be created to perform evil deeds as well as good.

In years gone by, macro viruses were common computer security threats. But, for the last several years, they have been much less significant because later versions of Microsoft Office disabled macros by default.

Alas, many users may have either forgotten about or have no knowledge of macro risks.

How do Criminals Use Macros to Distribute Malware?

Typically, malicious macros are distributed via emails that include seemingly harmless Microsoft Word or other types of Microsoft Office documents. The scam emails often masquerade as invoices, fax notifications, job applications, or various other common business messages.

When you attempt to open the attached document, you will be prompted to enable macros to view it. The prompt may claim that the document is protected for security reasons and you must turn macros on to access it. But, if you comply with the prompt, a malicious macro may then download and install malware on your computer.

Once installed, the malware may harvest information from your computer and send it to criminals. Or, it might lock up all of your computer’s files and then demand that you pay a ransom to unlock them.

You Will Never Need to Enable Macros to View Ordinary Documents

Do not believe any message that claims that you must enable macros in order to view a simple document such as an invoice or job application.  There is no valid reason why macros would need to be enabled to read such standard documents.

While macros can certainly be useful in some workflows, it is best to leave them disabled if you do not use them and are unfamiliar with their potential security risks.

More Information:

This report is a brief overview of a quite complex topic. If you would like to read more in-depth information about macro malware threats, the following resources should help:

Importance Notice

After considerable thought and with an ache in my heart, I have decided that the time has come to close down the Hoax-Slayer website.

These days, the site does not generate enough revenue to cover expenses, and I do not have the financial resources to sustain it going forward.

Moreover, I now work long hours in a full-time and physically taxing job, so maintaining and managing the website and publishing new material has become difficult for me.

And finally, after 18 years of writing about scams and hoaxes, I feel that it is time for me to take my fingers off the keyboard and focus on other projects and pastimes.

When I first started Hoax-Slayer, I never dreamed that I would still be working on the project all these years later or that it would become such an important part of my life. It's been a fantastic and engaging experience and one that I will always treasure.

I hope that my work over the years has helped to make the Internet a little safer and thwarted the activities of at least a few scammers and malicious pranksters.

A Big Thank You

I would also like to thank all of those wonderful people who have supported the project by sharing information from the site, contributing examples of scams and hoaxes, offering suggestions, donating funds, or helping behind the scenes.

I would especially like to thank David White for his tireless contribution to the Hoax-Slayer Facebook Page over many years. David's support has been invaluable, and I can not thank him enough.

Closing Date

Hoax-Slayer will still be around for a few weeks while I wind things down. The site will go offline on May 31, 2021. While I will not be publishing any new posts, you can still access existing material on the site until the date of closure.

Thank you, one and all!

Brett Christensen,