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SMEs and Small Businesses: How Can I Tell If My Company Has Been Hacked?

(And What to Do Before It’s Too Late)

It often starts with a small detail.

A colleague receives a strange email that appears to come from your address.
A server begins to slow down for no apparent reason.
An account logs out on its own, or an error message appears when everything was working fine the day before.

Nothing alarming at first glance — but the feeling grows that something isn’t right.

A company hack rarely looks the way people imagine. In most cases, it doesn’t begin with a ransom note but with a series of subtle, almost invisible signs.
Attackers aim to stay unnoticed: watching, copying, quietly extracting data.

Recognizing these early clues can be the difference between a minor incident and a long-lasting compromise.

The First Signs That Should Raise Concern

Certain behaviors in your systems or accounts should always trigger vigilance.

You notice unusual logins at hours when no one is working.
Audit logs show activity from a country where you have no clients.
Emails are sent automatically from your address — sometimes even using your usual signature.
Some users report sudden disconnections or password changes they never made.
The network occasionally slows down for no legitimate reason.
Or perhaps antivirus alerts appear, then vanish without explanation.

Taken individually, these signs may mean nothing. But together, they form a pattern. That’s often the moment when you should observe carefully rather than react impulsively.

When doubt arises, the usual reflex is to “reset everything”: restart the machines, delete suspicious files, or change all the passwords. That’s a common mistake — and sometimes an irreversible one.

Every action you take may erase critical digital traces: access logs, temporary files, timestamps, registry keys.
Yet these traces are essential to understanding what happened, identifying the vulnerability, and proving the source of an attack.
Before doing anything else, the goal is to stabilize the situation without destroying evidence.

Basic Checks — Without Destroying the Evidence

In most cases, the origin of a breach isn’t a sophisticated vulnerability — it’s an ordinary mistake.
A reused password. A misleading link. An access point left open.
Attackers don’t always need to force the door when it’s already slightly ajar.

That’s why cybersecurity isn’t just about firewalls and antivirus software — it’s also about habits and behavior.
Recognizing a suspicious message, segmenting access rights, or understanding that comfort and security rarely go hand in hand are all essential reflexes.

Start by documenting what you observe.
Write down the exact dates, times, and symptoms. Take screenshots. If possible, export access logs, activity reports, or security notifications.

In email accounts, check recent sign-ins and automatic rules created without your knowledge — such as redirects, copies, or filters.
On the network side, identify which sessions are open and which machines are communicating with each other.

And above all, do not install new tools without expert advice: many so-called “cleaning” programs erase artifacts that may be crucial for a forensic analysis.

Preserving the evidence is already a form of action.

When Should You Call in an Expert?

The rule is simple: call an expert as soon as there’s doubt about a compromise involving sensitive accounts — such as administration, finance, or professional email — or any possible exposure of client data.
If you can’t explain certain connections, or if your antivirus detects a threat but can’t remove it, professional intervention becomes essential.

The role of a specialist isn’t merely to “clean” infected systems. It’s first to understand what happened — to establish a timeline, preserve evidence, and identify the root cause.
That’s what allows a company to strengthen its security over the long term and, when necessary, respond to legal or insurance requirements.

Once the crisis has passed, the best decision is to turn the incident into a learning experience.
Prevention always costs less than recovery. Even a light annual security audit is often enough to avoid the worst.

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