Can I work without Microsoft Defender?

Technically, a computer can operate without Microsoft Defender. However, for a professional company, working without comprehensive endpoint security is not a responsible choice. Moreover, Microsoft Defender is an umbrella term for various security products: from the standard antivirus in Windows to full enterprise endpoint detection & response.

The main message:

A company device without professional endpoint security is an unnecessarily large risk today.

It does not necessarily have to be Microsoft Defender, but a full-fledged security solution must be in place.

What do we actually mean by "Defender"?

Microsoft uses the name Defender for various security products.

This regularly causes confusion.

There is an important distinction between:

Microsoft Defender Antivirus — the built-in antivirus protection of Windows;
Microsoft Defender for Business — business endpoint security for small and medium-sized organisations;
Microsoft Defender for Endpoint — more extensive enterprise endpoint detection & response;
other Microsoft Defender products for example for identity, email and cloud applications.

"We have Defender" by itself is therefore insufficient.
The relevant question is which Defender functionality is actually present, configured and monitored.

Can I disable Microsoft Defender Antivirus?

Windows can also be protected with another compatible antivirus or endpoint security solution.

In that case, depending on the configuration, Microsoft Defender Antivirus can take on a different role or leave the primary antivirus function to the other security product.

This is very different from:

"We turn Defender off and use nothing else."

We absolutely advise against the latter for company devices.

Why is classic antivirus alone no longer sufficient?

Traditional antivirus mainly focused on recognising known malware files.

Modern attacks work much more broadly.

Think for example of:

ransomware;
malware without classic virus files;
abuse of PowerShell or other legitimate tools;
credential theft;
phishing where the user executes something themselves;
exploitation of known vulnerabilities;
lateral movement within a network;
attacks that abuse legitimate Windows processes.

That is why modern security platforms look not only at files but also at behaviour.

What is EDR?

EDR stands for Endpoint Detection & Response.

An EDR solution not only tries to block malware but also monitors suspicious activities on the device.

A professional EDR solution can, for example, help detect:

unusual processes;
suspicious scripts;
credential dumping;
ransomware behaviour;
suspicious network connections;
abuse of system tools;
multi-step attacks.

The difference:
antivirus mainly asks "is this file malicious?", while EDR also asks "is this device behaving suspiciously?"

Why is that so important?

Many modern attacks specifically try to bypass traditional antivirus detection.

An attacker does not necessarily have to install a classic virus file.

They can, for example:

abuse a valid user account;
use PowerShell;
abuse an existing remote management tool;
execute scripts;
use legitimate system components for malicious purposes.

A device can therefore be seriously compromised without a single classic "virus.exe" file present.

Does it have to be Microsoft Defender?

No.

There are various professional endpoint security and EDR platforms.

The right solution depends, among other things, on:

the size of the organisation;
the Microsoft licences used;
the desired security level;
the management environment;
other security products already in use;
how monitoring and incident response are organised.

The real requirement is not "everyone must use exactly the same security product".
The requirement is that every company laptop is professionally and demonstrably protected.

What should a professional endpoint security solution at least be able to do?

FLEXAMIT expects much more than just an antivirus scanner for a professional business environment.

Depending on the environment, we look at, among other things:

real-time malware protection;
behaviour detection;
EDR;
cloud-based threat intelligence;
protection against ransomware;
attack surface reduction;
central policies;
central monitoring;
alerting;
investigation of incidents;
isolation or other response options;
reporting and auditing.

A green checkmark next to "antivirus active" is insufficient proof of good endpoint security in a professional environment.

Detection without follow-up is also insufficient

This is at least as important as the security product itself.

Suppose an EDR platform detects a serious attack at 02:17 AM.

Then someone must know:

that the alert exists;
how serious it is;
which device is affected;
which user is involved;
whether the device needs to be isolated;
whether credentials may have been stolen;
whether other devices need to be investigated.

A security alert that no one looks at hardly protects your company.

That is why monitoring is so important

Professional endpoint security consists of two parts:

1. Technology
The endpoint security solution detects and blocks suspicious activity.

2. Follow-up
Alerts are assessed and action is taken in the event of a serious incident.

Both are necessary.

"We are just a small company"

Even a small company can be affected by:

ransomware;
phishing;
credential theft;
malware;
a hacked supplier;
a vulnerable application.

Small companies also often have less internal IT capacity to resolve an incident themselves.

Your company does not have to be large to be interesting to cybercriminals.
Many attacks are automated and search for vulnerable organisations, not for a specific staff size.

"But we have a firewall"

That is good, but a firewall does not replace endpoint security.

A laptop can, for example, be attacked:

via phishing;
via a malicious document;
via a browser;
via a stolen account;
when the employee works from home;
when the laptop is outside the company network.

Firewall, identity security and endpoint security protect different parts of the environment.

"But everyone uses Microsoft 365"

That does not make endpoint security redundant either.

SaaS reduces certain risks of classic local infrastructure, but employees still work from physical devices.

On those devices:

files are opened;
web content is executed;
Microsoft 365 tokens are used;
passwords and other credentials are entered;
files are synchronised;
business applications are used.

A cloud company still has endpoints. And those endpoints must be protected.

"Our people don’t click on suspicious links anyway"

Security should never be entirely dependent on perfect user behaviour.

Even experienced employees can:

open a convincing phishing email;
end up on a fake login page;
open the wrong file;
accidentally approve an MFA request;
install a seemingly legitimate application that turns out to be malicious.

Good security assumes people can make mistakes and builds technical safety nets around that.

Endpoint security is only one layer

Even the best endpoint security does not make an organisation invulnerable.

A mature security model combines several layers:

MFA and passkeys;
Conditional Access;
endpoint security and EDR;
device management;
email protection;
firewall and network security;
patch management;
password management;
backup;
security awareness;
monitoring and incident response.

Cybersecurity works best as a system of multiple defence layers.

So can I work without Microsoft Defender?

Yes, when another full-fledged business endpoint security or EDR solution correctly takes over that security role.

But the more important question is:

"Can my company operate without professional endpoint security?"

Our answer to that is clear: we absolutely advise against it.

A professional company device without active, centrally managed endpoint security creates an avoidable and substantial security risk.

How does FLEXAMIT approach this?

FLEXAMIT does not start from the question of which logo is on the security product.

We look at the complete security architecture.

In doing so, we assess, among other things:

which endpoint protection is used;
whether EDR is present;
whether devices are centrally managed;
whether security policies are correctly configured;
how quickly security updates are rolled out;
whether alerts are actually followed up;
how incident response is organised;
how endpoint security connects with identity, email and network security.

FLEXAMIT considers professional endpoint security an absolute foundational layer of cybersecurity.

We don’t just want software installed on a laptop.

We want:

security to be correctly configured;
the device to be continuously protected;
suspicious activity to be detected;
alerts to be visible;
serious incidents to be effectively investigated and followed up.

Only then do you have a security solution instead of just an antivirus licence.

Why FLEXAMIT is a strong partner for this

Endpoint security never stands alone.

An incident on one laptop can directly lead to:

stolen Microsoft 365 credentials;
access to company data;
ransomware;
abuse of email accounts;
attacks on other systems;
data leaks.

That is why FLEXAMIT combines endpoint security with:

Microsoft 365 security;
Microsoft Entra;
Conditional Access;
Intune;
email security;
password management;
firewall and network security;
backup;
monitoring;
security awareness.

The goal is not to install as many security products as possible.

The goal is to build a coherent security environment in which each layer supports the other.

FLEXAMIT tailors that security to your organisation so that it maximally protects without unnecessarily hindering employees.

Our cybersecurity expertise has been recognised three years in a row by our Microsoft distributor with the Cybersecurity Partner of the Year award.

Don’t know how your devices are secured today?

That alone is a good reason to have it checked.

FLEXAMIT can assess:

which endpoint security is active;
whether all devices are protected;
whether EDR is correctly set up;
whether policies are sufficiently strict;
whether alerts are followed up;
whether users can bypass security settings;
whether endpoint security integrates well with Microsoft 365 and the rest of the environment.

In summary

Microsoft Defender is an umbrella term for various Microsoft security products.
The built-in Microsoft Defender Antivirus is not the same as a full-fledged EDR platform.
A company can replace Microsoft Defender with another professional endpoint security solution.
However, a company device without professional endpoint security is not a responsible choice.
Modern attacks require more than traditional antivirus detection.
EDR also looks at suspicious behaviour on an endpoint.
Central monitoring and follow-up of alerts are at least as important as the software itself.
A firewall or Microsoft 365 does not make endpoint security redundant.
Even small companies need professional endpoint protection.
Endpoint security must work together with identity, email, network, backup and other security layers.
The question is therefore not whether you can do without Microsoft Defender, but whether you can do without professional endpoint security. Our advice: absolutely not.

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