How Malware Hides in Business Communication

Most cyberattacks these days don’t look like something out of a movie. No dramatic hacking scenes, no blinking red alerts. Just… an email. A simple, harmless-looking email with a file or a link that someone on your team clicks without thinking twice.

That’s how it usually starts. 

Hackers have gotten really good at blending in, posing as clients, vendors, or even coworkers. They don’t need to force their way in when they can just ask to be let in. One message about a new order or an updated invoice is all it takes to drop spyware into your system or open the door to a full-blown breach.

Let’s find out how modern malware hides in business communication and what you can do to prevent its damage to your business!

How Attackers Sneak Malware into Business Emails

Hackers hide malware in everyday-looking messages that slip right into your inbox. Here’s how:

• Fake orders or invoices: A zipped “New Order” file hides spyware like Agent Tesla. Open it, and the infection begins.
• Malicious PDFs: A clean looking PDF includes one link. Click it, and you unknowingly download malware like Formbook.
• Hijacked conversations: Attackers take over a real vendor’s email and reply to existing threads but now with a dangerous attachment.
• Spoofed internal messages: Emails that look like they’re from your team may carry malware-packed files or shady links.

How to Uncover What’s Hiding Behind the Click

With solutions like the ANY.RUN interactive sandbox, you can safely inspect suspicious emails, attachments, and links before they reach your team. It runs the file in a controlled virtual environment and shows exactly what happens, from file drops to network connections, in real time.

Let’s have a look at 2 real-world examples of hidden malware and discover how they can be easily detected inside the sandbox.

Example 1: Agent Tesla Hidden in a “New Order” File

By opening the suspicious email inside ANY.RUN’s sandbox, we can see how it looks and where it’s hiding the malware.

View analysis session

A phishing email arrives with a zipped file named “New Order.” Inside is a .exe program pretending to be a document. When opened, it deploys Agent Tesla; a keylogger and data-stealer.

Give your team the solution they need to catch hidden threats before they cause damage with ANY.RUN’s interactive sandbox.

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When analyzed in ANY.RUN, the sandbox immediately flags suspicious activity in the top-right corner of the screen and clearly labels the malware as Agent Tesla. It’s one of the fastest ways to confirm whether a file is dangerous.

Malicious activity detected by ANY.RUN interactive sandbox

In the Process Tree, you can click on the malicious process to see the exact Tactics, Techniques, and Procedures (TTPs) used during the attack, giving you instant insight into what’s happening behind the scenes.

The process of Agent Tesla with its TTPs

You can also check the TTPs in more details by clicking on the ATT&CK button on the right upper side of the screen. By clicking on the technique, you get the explanations for each technique.

To break it down even further, just click the ATT&CK button in the upper-right corner. There, you’ll see the mapped MITRE TTPs used in this attack. Click on any technique to view detailed explanations and understand exactly how the malware operates.

MITRE ATT&CK Matrix techniques and tactics used in the attack

Example 2: Formbook Delivered Through a Fake PDF

Here is another example of a hidden malware analyzed inside ANY.RUN sandbox. 

View analysis session

Malicious PDF file analyzed inside ANY.RUN sandbox

The email contains what looks like a regular PDF attachment. But open it, click the link inside, and it downloads an archive hiding Formbook, another infostealer.

Suricata rule triggered by Formbook inside ANY.RUN sandbox

Don’t Let Malware Slip Through Everyday Conversations

The most dangerous threats are often the ones that look ordinary, a fake order, a familiar-looking PDF, or an email from a trusted partner. These aren’t just clever tricks, they’re active threats that can steal data, compromise your systems, and go unnoticed until it’s too late.

Solutions like ANY.RUN give businesses a crucial edge. Instead of guessing, you can see exactly what a file or link does in real time, in a safe, isolated environment. From automatic threat labeling to detailed TTP breakdowns, it gives your team the clarity they need to act fast and stay ahead of attackers.