Microsoft Office End of Life: Why Malicious Macros Are the Next Big Security Headache

Are you planning your migration away from Microsoft Office 2016 or 2019—or perhaps still weighing whether to take the leap? If so, you’re not alone. With Microsoft setting the end-of-life (EOL) deadline for these ubiquitous productivity suites in October 2025, IT teams everywhere are heads-down, plotting their next moves. But as you map out your path to Windows 11 or even weigh the bold jump to open-source alternatives like LibreOffice, there’s a critical issue you can’t afford to ignore: malicious macros and the security risks they pose—no matter which office platform you choose.

Let’s unravel what all this means for organizations, how attackers exploit macros, and—most importantly—how you can proactively protect your business, data, and users in a rapidly shifting technical landscape.

The Microsoft End-of-Life Domino Effect: More Than Just Upgrading Software

It’s tempting to see end-of-support dates as simple to-do list items: upgrade, migrate, move on. But software EOL is more domino run than checklist—especially in the enterprise world, where whole workflows, compliance requirements, and legacy automation hinge on decades-old tools.

Here’s why that matters: When Microsoft sunsets support for Office 2016, 2019, Exchange 2016, and Exchange 2019 in October 2025, it’s not just bug fixes and feature updates that disappear. It’s the critical security patches that stand between your organization and an entire world of evolving cyber threats. Microsoft’s own EOL page makes it clear: unsupported means unprotected.

Meanwhile, Windows 10’s own looming end-of-life (October 2025) is already triggering mass IT scrambles. And with Denmark, for example, piloting a switch from Microsoft 365 to LibreOffice, we’re seeing even government entities rethink their reliance on the traditional Microsoft stack.

But making the move—whether to Windows 11, a cloud-first Microsoft 365, or a non-Microsoft alternative—means re-examining your security posture from the ground up. Nowhere is this more urgent than with office document macros.

Why Macros Still Matter—And Why Attackers Love Them

Before we dive into the risks, let’s quickly level-set: what is a macro, and why do they matter so much in business environments?

Macros are scripts—often written in Visual Basic for Applications (VBA)—that automate repetitive tasks inside documents, spreadsheets, and presentations. Think: auto-filling forms, crunching data, or running custom workflows at the click of a button. They’re productivity powerhouses, and many organizations have built entire lines of business on macro-driven automation.

But here’s the rub: macros can also be Trojan horses for attackers.

How Malicious Macros Work (And Why They’re So Dangerous)

Attackers love macros because they’re a “trusted” way to execute code inside your organization’s perimeter. A cleverly crafted document can:

Steal sensitive data by running hidden scripts.
Corrupt files or spread malware and ransomware across your network.
Bypass security controls that would otherwise stop downloaded executables.
Trick users via phishing by asking them to “enable content” on seemingly benign documents.
Launch fileless attacks that live only in memory, making detection much harder.
Spread via insiders—through accidental sharing or use of unvetted code.

With organizations still depending on macro-laden templates and legacy documents, malicious macro attacks remain one of the top cyber threats today. Even as Microsoft has tightened macro protections in its 365 cloud, the attack surface remains broader (and stealthier) than many realize.

Migration Woes: Macros Don’t Always Play Nice

Let’s say you decide to leave Microsoft Office behind—maybe you’re inspired by Denmark’s LibreOffice experiment, or perhaps budget and compliance pressures make open source appealing. Here’s where reality hits:

Macros rarely migrate seamlessly. There’s no one-click converter from VBA macros to LibreOffice Basic or other scripting languages. You may lose critical business automations overnight.
Templates may break. Heavily customized document templates, built over years, often contain embedded macros or references that won’t work outside Microsoft’s ecosystem.
User retraining is needed. Even subtle UI and scripting differences can throw off staff, risking productivity and creating new helpdesk headaches.
Security features differ. LibreOffice, for example, may not warn users as aggressively about untrusted macros as Microsoft Office does—a gap attackers are already probing.

Personal experience tells the tale: Migrating from Lotus 1-2-3 to Excel wasn’t just about importing sheets. We had to hire external consultants to rewrite key scripts and templates. It wasn’t trivial—and today, the stakes (and risks) are even higher.

The Six Faces of Malicious Macro Attacks

Let’s dig deeper. No matter your platform of choice—Microsoft Office, LibreOffice, or any other—these are the six main types of malicious macro threats you need to address:

1. Malicious Code Execution

Attackers embed scripts that auto-run when a document opens. These scripts might:

Send sensitive files to an external server
Install hidden backdoors
Alter system settings for persistence

2. Macro-Based Malware and Ransomware

Threat actors craft macros that download and install malware, often encrypting files or locking users out until a ransom is paid. The NotPetya attack, for example, used macro-laden documents as a launchpad.

3. Bypassing Security Controls

Macros can be used to sidestep antivirus or endpoint protections, for example by spawning child processes or obfuscated script launches that evade detection.

4. Phishing & Social Engineering

Phishing emails with seemingly legitimate attachments often prompt users to “enable macros.” One click—and the attacker is inside.

5. Fileless Attacks

Some modern macro threats live entirely in memory. They don’t drop files on disk, making them invisible to traditional AV scans.

6. Insider Threats & Accidental Spread

Even well-meaning employees can propagate bad macros by sharing old templates or using unvetted code found online.

Bottom line: No organization is too small or “boring” to be targeted. Macros are low-hanging fruit for attackers, and EOL migrations make for perfect cover.

LibreOffice vs. Microsoft Office: The Security Tradeoffs

You might be thinking: “If macros are risky, why not just block them altogether, or move to a platform that’s less ‘friendly’ to macros?” Fair question. But the answer isn’t so simple.

LibreOffice: Familiar Vulnerabilities, New Challenges

LibreOffice supports macros, too. While it doesn’t natively use VBA, it allows scripting in its own language. Unfortunately, recent security CVEs—like CVE-2025-1080—show attackers are already finding creative ways to exploit macro behavior in LibreOffice, sometimes with even fewer warning prompts than Microsoft Office provides.

Here’s the catch: LibreOffice’s security model relies more on user vigilance. In many organizations, that’s a recipe for accidental enablement and social engineering.

Microsoft Office: More Granular Controls

Microsoft has spent years hardening macro security, especially in Office 365. Features like:

Protected View for files from the Internet
Digital signature enforcement
Granular group policy settings
Attack Surface Reduction (ASR) rules

…all give IT teams more ways to lock down risky behavior. But as older versions fall out of support, these protections may no longer receive critical updates, opening the door to innovative attacks.

Migration is never just about costs or licenses—it’s about how you’ll keep users safe when the familiar guardrails disappear.

Harden Your Defenses: Proactive Macro Security Strategies

Whether you’re sticking with Microsoft, venturing into open-source territory, or running a hybrid environment, here’s how to protect yourself against malicious macros:

1. Inventory and Audit Your Macros

Start by mapping out where macros are used in your organization. Ask:

Which documents, templates, or workflows depend on macros?
Are they still necessary, or can they be replaced with built-in features?
Who authored them—and are they digitally signed and trusted?

Tip: Documenting your macro landscape is essential before any migration.

2. Implement Strict Macro Policies

For Microsoft Office, leverage all available controls:

Block macros from running in documents from the Internet via Group Policy.
Require macros to be digitally signed—and only run trusted signatures.
Disable macros entirely whenever possible, especially for user groups that don’t need them.
Educate users: Train staff to recognize risky prompts and avoid enabling macros in unsolicited files.

If using LibreOffice, set organizational policies to restrict macro execution and ensure employees understand the risks.

3. Leverage Attack Surface Reduction (ASR) Rules

ASR rules are a powerful feature in Microsoft Defender for Endpoint that help contain macro-based attacks. If you rely on macros but want to mitigate risk, enable these critical rules:

Block Office apps from creating child processes
Block execution of potentially obfuscated scripts
Block JavaScript or VBScript from launching downloaded executable content
Block Office apps from creating executable content
Block Office communication apps from creating child processes
Block Win32 API calls from Office macros
Enable advanced ransomware protection

For detailed ASR guidance, see Microsoft’s ASR documentation.

4. Modernize Automation Where Possible

Ask yourself: Do I still need macros, or can newer tools accomplish the same workflows?

Consider: – No-code platforms like Power Automate for workflow automation – Built-in Excel functions such as XLOOKUP, LAMBDA, or Power Query – APIs and connectors (e.g., Microsoft Graph) for integrating processes

These alternatives are easier to maintain, monitor, and secure—and are less likely to be weaponized by attackers.

5. Don’t Forget Mac Security

Think macOS is immune? Think again. Office for Mac uses the platform’s sandboxing for protection, but macro threats still exist. IT should:

Disable the VBA object model
Disable Visual Basic system bindings
Block external library, pipe, and AppleScript bindings for VBA
Monitor for rogue macro behavior

For Apple-specific guidance, check resources like Apple’s security documentation.

6. Plan for the Human Factor

Your defenses are only as strong as your least-informed user. Continuous training, simulated phishing, and regular security reminders are essential. Also, encourage a culture where employees feel comfortable reporting suspicious files or macro prompts.

What About Complete Macro Disablement?

For some, the question is: “Why not just turn macros off, everywhere?” And yes, if you can, that’s the safest route! But for industries with heavy automation, legacy processes, or regulatory requirements, that’s easier said than done.

If you must use macros: – Audit and reduce usage to the bare minimum. – Require digital signatures. – Keep a tight chain of custody and version control. – Continuously review for better alternatives as platforms evolve.

Real-World Example: Lessons from Denmark’s Leap to LibreOffice

When Denmark announced plans to test phasing out Microsoft 365 for LibreOffice, it wasn’t just a cost-saving measure. It was a calculated risk, driven by security, data sovereignty, and control.

Here’s what their journey teaches us:

Any migration must include a thorough inventory of legacy automations—including every last macro.
Significant effort is needed to manually convert or rewrite business-critical scripts.
New platforms bring new security models. What worked in Microsoft may not map 1:1 to LibreOffice, and vice versa.
Communication, change management, and user retraining are every bit as important as technical migration.

Frequently Asked Questions (FAQ)

1. What is the end-of-life date for Microsoft Office 2016 and 2019?

Microsoft Office 2016 and 2019, as well as Exchange 2016 and 2019, reach end of support on October 14, 2025. After this date, these products will no longer receive security updates. Read more from Microsoft.

2. Are macros in LibreOffice safer than in Microsoft Office?

Not necessarily. While LibreOffice uses a different macro language, attackers have already found ways to exploit macro functionality. LibreOffice may also provide fewer security prompts by default. Regardless of platform, strict macro policies and user training are essential.

3. Can all Microsoft Office macros be migrated to LibreOffice automatically?

No. There is no direct, automated way to convert VBA macros to LibreOffice macros. Manual rewriting and testing are usually required.

4. What are Attack Surface Reduction (ASR) rules, and how do they help?

ASR rules are security controls in Microsoft Defender that help block common exploit techniques—such as Office macros spawning malicious processes. They’re a must-have for any organization that allows macros.

5. Are Macs vulnerable to macro-based attacks?

Yes, especially if users open untrusted documents or enable macros. Office for Mac provides some protections, but IT should also set specific preferences to limit macro capabilities.

6. Should my organization disable macros entirely?

If feasible, yes—it’s the most secure option. But if legacy workflows must use macros, apply strict controls, limit their use, and keep everything signed and up-to-date.

7. What are the risks of staying on unsupported Office products?

Without security updates, you’re exposed to newly discovered vulnerabilities, including macro-related attacks. Attackers often target EOL software because they know organizations can’t patch new holes.

8. Where can I find more information about secure Office migrations?

The Takeaway: Security is a Journey, Not a Checkbox

The end of life for Microsoft Office 2016 and 2019 is more than a licensing event—it’s a wake-up call for organizations to rethink automation, security, and risk. Whether you’re staying in the Microsoft ecosystem, exploring open source, or running a mix of both, malicious macros remain a top threat vector.

Here’s what you can do, starting today: – Inventory and audit all macro use (and eliminate wherever possible) – Apply granular security controls and ASR rules for those that remain – Explore modern automation and no-code alternatives – Train and empower users to recognize and report macro threats – Stay engaged with updates from Microsoft, LibreOffice, and cybersecurity authorities

Want more insights on securing your digital workplace? Subscribe to our blog or explore our guides on secure migration, automation best practices, and the future of office productivity.

Your business deserves more than “good enough” security. Prepare now—because attackers don’t wait for EOL dates.

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