All you need to know about malware, the virus that doesn't wait for winter to strike!

More than half of all companies were victims of a cyber attack in 2023. The culprit? Malicious software, commonly known as malware.

While the Hiscox 2023 report highlights this alarming reality (53% of companies affected!), the exact nature of these threats and how to protect against them often remain obscure.

This article will tell you all you need to know about malware. On the program: an explanation of what malware is, an overview of the worst digital parasites, practical tips for recognizing the dangers, and a short guide to effective digital protection.

Let's get started!

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What is malware?

The term " malware " comes from the contraction of malicious software. But beware: it's not just a computer virus that hangs around in your files doing nothing.

"Malware" is a generic term that encompasses a whole family of software developed for a single purpose: to do harm to your computer system, your data or your business.

Malware can :

• spy on your activities ;
• steal sensitive information;
• destroy files;
• completely block a network and demand a ransom.

It can be compared to a digital burglary: it breaks into your home, often without your knowledge, rummages around, steals what it wants... and sometimes even leaves a note ( ransomware).

The 6 most common types of malware

#1 The virus

The computer virus is a bit like the old school of malware. It doesn't just infect a file: it seeks to replicate itself to infect other programs or machines. It often acts by stealth, waiting for the infected file or application to be launched.

Historically widespread in the 90s and 2000s, it is less common today, as other, more sophisticated forms have gradually replaced it. But it remains active, especially in contexts where systems are not regularly updated.

A virus can have several effects:

• system slowdown ;
• file corruption ;
• application malfunction ;
• even complete data destruction.

It is often used as an entry vector for other types of malware.

☝️ Note that some modern viruses no longer seek to destroy, but to discreetly exfiltrate data. Their authors focus on persistence rather than immediate chaos.

#2 The Trojan horse

📖 You know the story: the Greeks offer the Trojans a huge wooden horse. A poisoned gift, since inside it lurked soldiers ready to invade the city.

In cybersecurity, it's exactly the same thing. A Trojan horse can take the form of an innocuous file, application or even e-mail. An update, an invoice, an attachment with a reassuring title... Once executed, it opens a backdoor in your system.

This "backdoor" enables the attacker to gain remote access to your machine, often without you even realizing it.

He can then observe, exfiltrate data, install other malware or take control of all or part of the system.

💡 This type of malware is particularly used in targeted attacks against businesses. Cybercriminals use it to prepare the ground for a more massive attack: data theft, encryption via ransomware, sabotage, etc. In short, with Trojans, the packaging is pretty, but the inside is rarely festive.

#3 Ransomware

Ransomware is probably the most feared in the professional world.

Ransomware encrypts all data on a workstation or network, then demands a ransom to provide the decryption key. In plain English: your documents, databases and business tools become inaccessible... you can no longer use any application, and must pay a ransom to get your tools working again. This type of cyberattack affects a significant number of companies.

⚠️ Some organizations prefer to pay to get back up and running quickly, but beware: there's no guarantee that cybercriminals will keep their promise.

LockBit, Conti and Ryuk are just a few of the known ransomware programs that have already paralyzed hospitals, local authorities, industrial groups... and SMEs. Another fact to know: a Sophos study estimates the average cost of a ransomware attack at around €1 million. These costs include the ransom, estimated at 142,000 euros on average, but also business interruption, reputation... and crisis management.

#4 Spyware

This malicious program is a spyware program that operates in total stealth. It surreptitiously spies on your every move: what you write on your keyboard, what appears on your screen, where you surf, etc. This makes it particularly dangerous if you're dealing with a spyware program.

This makes it particularly dangerous if you're handling sensitive or confidential information such as passwords or credit card numbers. It is often installed via a Trojan horse or a security hole.

Some versions are even capable of activating the host device's camera or microphone, without your knowledge. You can easily imagine how dangerous it can be in a professional context.

Hidden by nature, spyware can provide strategic information to competitors over a long period of time, or lead to massive leaks of customer data.

#5 Adware

Adware (advertising software) is a highly invasive advertising virus. Once you're infected, the worm spreads and floods you with ads, often pop-ups.

Do you find it annoying, but harmless? Just remember that it can considerably slow down a system or redirect your searches to dubious sites.

This type of software is usually a gateway to the worst. And if it doesn't steal data per se, it can act as a gateway to more virulent malware.

☝️ Some adware also records behavioral data for resale to third parties. If you find yourself infected by this type of malware, remain vigilant and secure the security hole as quickly as possible.

#6 The rootkit

The rootkit, also known as stealth malware, is the king of stealth. 🥷

This software hides in the deepest layers of the system, making it very difficult to detect. It is also highly dangerous, since it enables an attacker to take total control of a system, often masking his own presence and that of other malware.

Its name derives from the fact that it gives remote root (administrator) access, undetected by conventional antivirus programs.

This type of attack is formidable in corporate environments, as it can allow the attacker to remain in a system for several weeks, or even months, without arousing suspicion, gathering information, creating vulnerabilities and preparing a larger-scale attack.

In other words, it's better to be able to detect malware intrusion on your machines quickly!

How to recognize a malware infection

To protect yourself from malware, you need to be able to recognize the symptoms of infection quickly. Certain unusual behaviors should immediately alert you.

For example, you may notice

• your computer is slowing down for no apparent reason;
• programs, windows or applications launching on their own;
• strange error messages appear without explanation;
• many intrusive advertisements appear;
• your browser has changed search engine without you doing anything.

All these symptoms are signs that malicious software has compromised your IT security. In a professional environment, a simple piece of spyware can be enough to compromise sensitive data or leak strategic information. It is therefore essential to know how to remove the different types of malware.

How do I remove malware?

Once you've been able to identify with certainty the malware infecting your computer, here's how you can go about removing it.

Steps to follow

• First, disconnect the device from the Internet. By being offline, you prevent the hacker from controlling your computer in real time via remote access. This also prevents the risk of damaging your computer network.
  
  
• Restart in safe mode. Whether you're running Windows or another operating system, this is easy to do.
  
  
• Scan with a reliable antivirus. The aim is for your antivirus to detect which files may have been damaged by the malicious attack.
  
  
• Delete or quarantine infected files. If a virus infects one file, the worst thing is for it to spread to others. So it's best to isolate or delete them to avoid this. If you have files that require special vigilance, it's a good idea to have a backup in case you need to delete a version.
  
  
• Update your system and software. Sometimes, your computer vulnerability can be explained simply by the use of obsolete tools. By keeping up to date, you reduce the risk of encountering other malware via the same vulnerability.
  
  
• Change your passwords. Once you've cleaned up, don't forget to change your access rights, and reinforce them if possible.

And if nothing works?

As a last resort, you should consider reformatting your device.

Or call in a cybersecurity professional. Removing malware is sometimes difficult and not without risk to do yourself.

For the rest, remember that prevention is the key to effective protection.

How can I protect myself from malware?

1. Train your teams (especially non-techies)

The biggest vulnerability factor in your IT security is often the human aspect.

You can have the best malware detection tools, but if your team doesn't know how to use them, your protection will be useless.

In this respect, training is your best weapon and your first lever of action. Most hackers achieve their goals by exploiting a human vulnerability. For example, a well-known method is to send an e-mail urging people to click on dubious links, or download an attachment.

💡 A culture of cybersecurity is essential to protect yourself! To develop collective vigilance, you need to get everyone to adopt the right reflexes. A simple idea to accompany this training is to incorporate simulation exercises (phishing, risky behavior, etc.). These exercises help to transform theoretical awareness into lasting behavior.

2. Implement a genuine ISSP

An Information System Security Policy (ISSP) is essential for effective protection.

More than just a document, the ISSP is your cybersecurity backbone. A well-designed ISSP establishes the best practices you need to protect yourself:

• limiting access according to roles ;
• impose strong, regularly modified passwords;
• generalize multi-factor authentication;
• establish clear procedures for responding to incidents.

☝️ An ISPP is only useful if it is understood, applied and updated in line with your needs. All these secure best practices need to be communicated to your staff, including external service providers.

3. Choose the right tools

The IT manager's toolbox has expanded considerably in recent years.

Next-generation antivirus, intelligent firewalls, corporate VPNs and more. The challenge is to choose solutions that are :

• compatible with each other;
• well configured;
• adapted to your environment.

So, before you invest, ask yourself the right questions: What is your level of risk? Which workstations or servers are the most sensitive? Who administers what? Do your teams know how to interpret an alert?

Once you have the answers, you'll be able to find the right tools depending on the number of workstations to be secured, the degree of danger and how complex you can afford to use them.

💡 In all cases, give preference to tools capable of centralizing alerts and generating clear reports. You'll save time... and peace of mind.

4. Update. Always.

There's no secret about it: IT security is a constantly evolving sector, and cybercriminals are making progress too.

They have a well-honed routine: they scan for known vulnerabilities. Unpatched vulnerabilities become their preferred entry points. To counter this and keep your tools operational, you need to make sure they're up to date. You need to update everything on a regular basis.

The operating system? Essential.

Business software? Also.

Browsers, extensions, plugins? Absolutely.

Network devices? Of course (we all too often forget routers, NAS, connected objects).

Every obsolete version is a potential security breach. And in a world where the reaction time between the discovery of a flaw and its exploitation by a hacker is sometimes counted in hours, responsiveness is your best ally.

💡 The best thing to do is to set up an automated patch management policy, with alerts in case of failure. Then test critical updates on a pilot machine before full-scale deployment.

5. Back up regularly

Last but not least: back-up.

Because even with all the precautions in the world, an incident can still happen. And when it does, you need to be able to restore your business... without panicking (or paying a ransom).

To avoid losing everything overnight, don't put off your backups. Hackers don't wait for your next meeting to attack.

Implement a backup strategy that includes both local (hard disk, internal server) and cloud backups. Make sure backups are automated, encrypted and tested regularly. Because a malfunctioning backup is like a disconnected alarm.

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Malware in a nutshell!

Now you know more about malware, which refers to any form of malicious software. You know just how dangerous they are: they can spy on and steal your data. They can even block your computer.

Whether in the form of viruses, Trojans, ransomware or anything else, the key is to know how to spot and remove them, but above all to prevent them from entering your computer system.

The key to this is good digital hygiene. Start building a culture of cybersecurity now. What about tomorrow? With AI and connected objects ... malware could change shape. But the challenge remains the same: protecting machines and sensitive data.