The cyberattacks that affected several French government services during the summer of 2026 have once again shown that no organisation is immune.
An intrusion into a critical information system can compromise sensitive data, disrupt essential applications and, in some cases, interrupt business operations.
As threats continue to evolve, protecting an IT infrastructure cannot rely on a few isolated security tools. It requires a comprehensive strategy that can identify vulnerabilities, strengthen defenses and prepare the organisation to respond in the event of an attack.
So, how can you effectively protect critical IT infrastructure against cyberattacks? Discover the essential measures you can implement to reduce risks and strengthen your organisation’s resilience.
Why protect critical IT infrastructure against cyberattacks?
Critical IT infrastructure brings together resources that are essential to a company’s operations. A successful attack can therefore go far beyond a simple IT incident. It can affect operations, employees and customers, and sometimes lead to business disruption.
What is critical IT infrastructure?
An IT infrastructure is considered “critical” when it hosts or enables essential services that the company relies on to operate. Even temporary downtime can have significant consequences for the organisation.
Depending on the environment, it may include:
- The network;
- Servers;
- Workstations;
- Security equipment;
- Business applications;
- Cloud solutions;
- Systems that store and process sensitive data.
The level of criticality therefore depends directly on business needs. In retail, for example, a network or payment system outage can prevent a store from processing customer transactions. In banking or insurance, the unavailability of a business application can disrupt access to essential services or information.
IT infrastructure security is therefore both a business continuity and a cybersecurity issue. The more a company relies on its information system, the more it needs to anticipate the risks that could compromise its operations.
What threats can compromise your information system?
Cyberattacks can take many different forms. Some directly target infrastructure. Others exploit human error or a vulnerability to gain initial access to the information system.
The main threats a company may face include:
- Ransomware, which can encrypt data or make systems and applications unavailable in order to demand a ransom.
- Phishing and credential theft, which allow cybercriminals to obtain passwords or other information to access company resources.
- Exploitation of vulnerabilities, particularly when systems, devices or software are not properly updated.
- Configuration errors, which can create unsecured access points on a network, server or cloud environment.
- Third-party compromise, when a service provider or partner with access to the system becomes the entry point for an attack.
An intrusion can then allow attackers to move through the network, access personal or sensitive data, disrupt services or compromise multiple systems. The consequences can be operational, financial and reputational.
Faced with these risks, the first step is not to multiply security tools. The company must first have a clear understanding of its environment and its security posture to identify which vulnerabilities need to be addressed as a priority.
Identifying vulnerabilities in your IT infrastructure
Before strengthening its defenses, a company needs to know where its weak points are. IT infrastructure is constantly evolving: new users, applications, equipment or cloud services can introduce new vulnerabilities. Regular assessment of the IT environment is therefore essential.
Map critical systems, data and access
A company cannot effectively protect what it does not know. Information system mappingprovides a clear view of the resources that make up the infrastructure, how they interact and their level of criticality.
The mapping should include:
- Equipment and servers;
- Business applications;
- Network infrastructure;
- Cloud services;
- Sensitive data;
- Users and their access rights.
These elements should then be prioritised according to their importance to business operations. In a retail environment, for example, the unavailability of a network device can affect several tools required to operate a site. Mapping therefore helps focus security measures on the most critical resources.
Regularly audit vulnerabilities and configurations
Mapping provides visibility into the environment. A cybersecurity audit assesses its security level and identifies weaknesses that could potentially be exploited.
The assessment can cover network configurations, user permissions, systems and software, Internet-facing services and the deployment of security patches. Depending on the organisation’s needs, vulnerability scans and penetration tests can provide additional insight.
These audits should be carried out regularly. A misconfiguration, an account that retains unnecessary privileges or software that has not been updated can introduce new risks. Regular checks help identify these weaknesses and address them before they can be exploited.
What measures should you implement to strengthen the cybersecurity of critical IT infrastructure?
Once vulnerabilities have been identified, the company can implement security measures tailored to its risk level. The objective is not to accumulate cybersecurity solutions. It is to combine several layers of defense to reduce the risk of intrusion, detect attacks quickly and protect the resources that are essential to business operations.
Secure networks, systems and access
Security starts with the network, which connects users, equipment, applications and data. Network segmentation separates different environments and limits an attacker’s ability to move laterally in the event of a compromise. If a workstation becomes infected, for example, segmentation can help prevent the attack from spreading directly to the most critical systems.
The company must also strengthen access management. Each user should only have the permissions required to perform their role. Multi-factor authentication, an appropriate password policy and the prompt removal of unused accounts help reduce the risks associated with credential theft.
Finally, IT teams must regularly update systems, software and equipment. A rigourous patch management process helps the risks associated to known vulnerabilities.
Monitor infrastructure and detect threats
Even with strong defenses in place, zero risk does not exist. Continuous monitoring of the infrastructure helps identify unusual behaviour more quickly, such as suspicious connections, repeated access attempts, abnormal server activity or unexpected changes to a system.
Monitoring and log management tools, as well as detection solutions such as EDR (Endpoint Detection and Response) and SIEM (Security Information and Event Management), can support this process. However, alerts must be configured and analysed according to the organisation’s needs. Too many unprioritised notifications can make it more difficult to identify a genuine threat.
Back up and protect critical data
A backup strategy is another essential layer of defense, particularly against ransomware. Critical data and systems should be backed up regularly, with copies sufficiently isolated from the main environment to prevent an attack from compromising them as well.
The company must also test backup restoration. Having a backup does not guarantee that it can be successfully restored when the organisation needs it. These tests help ensure that critical data can actually be recovered and directly contribute to business continuity.
Raise employee awareness of cybersecurity best practices
Protecting IT infrastructure does not rely on technology alone. Employees can also find themselves on the front line of cyberattacks, particularly when facing phishing campaigns or credential theft attempts.
Regular training helps reinforce best practices, such as checking the source of a message, protecting access credentials, quickly reporting suspicious activity and following company rules for the use of devices and data.
Awareness must be maintained over time. Threats evolve, as do the company’s tools and working practices. A shared cybersecurity culture complements technical measures and strengthens the overall level of protection across the information system.
How can you anticipate and manage a cyberattack?
Even with a high level of protection, no company can completely eliminate the risk of a cyberattack. The organisation must therefore know how to respond in the event of an incident. A well-prepared response helps limit the spread of an attack, protect critical resources and restore operations under the best possible conditions.
Prepare an incident response plan
An incident response plan defines the actions to take when an attack or intrusion is detected. It also establishes the role of each stakeholder to avoid uncertainty when every decision matters.
Depending on the nature of the incident, teams may need to isolate a device or part of the network, block certain access points, investigate the source of the attack and assess which systems or data have been compromised. They must also define the conditions required to restore services securely.
The relevant teams must be familiar with the plan, and the organisation should test it regularly. Exercises help ensure that procedures remain aligned with the current state of the information system and that teams know how to apply them in a real-world situation.état du système d’information et que les équipes savent les appliquer en situation réelle.
Plan for business continuity and disaster recovery
A cyberattack can make certain applications or infrastructure unavailable for several hours or even longer. The company must therefore determine in advance which services need to be restored as a priority and within what timeframes.
- Abusiness continuity plan (BCP) aims to maintain essential functions during an incident.
- A disaster recovery plan (DRP) organises the gradual return to normal operations.
These plans rely on backups, contingency solutions and previously tested restoration procedures.
This preparation strengthens the company’s resilience. When facing an attack, the objective is no longer simply to prevent an intrusion. It is also to limit its impact and enable the organisation to continue or resume operations as quickly as possible.
Conclusion
Protecting critical IT infrastructure against cyberattacks requires a comprehensive approach. Security depends as much on understanding your environment as it does on securing networks and access, monitoring infrastructure, protecting data and preparing for a potential attack. These measures must also evolve alongside new threats, working practices and business needs.
To strengthen your information system over the long term, it is therefore essential to adopt a cybersecurity strategy tailored to your business operations and level of risk.
Digital Novva Partners’ experts support you in securing, monitoring and evolving your IT infrastructure, with solutions tailored to your environment and business challenges. Discover our areas of expertise and services to strengthen the security and resilience of your information system.
Q&A
What are the first measures you should take to protect IT infrastructure from a cyberattack?
The first step is to gain a clear understanding of your infrastructure and identify the most critical resources for your operations. The company should then assess its vulnerabilities and prioritise risks.
It can then strengthen its main defenses:
- Secure access;
- Segment the network;
- Update systems and software;
- Protect workstations;
- Back up sensitive data.
These measures should be adapted to each organisation’s environment and needs.
How often should you conduct a cybersecurity audit?
There is no single frequency that works for every company. The appropriate schedule depends on the organisation’s risk level, the criticality of its information system and how quickly it evolves. An audit should also be considered after a significant infrastructure change, the deployment of new applications or a security incident.
How should you respond to an intrusion into your information system?
In the event of an intrusion, the company must act quickly while avoiding rushed actions that could erase information needed to investigate the incident. It should activate its response plan, involve the appropriate experts and isolate compromised systems when necessary.
Teams must then assess the extent of the attack, secure affected access points and gradually restore services. A post-incident analysis can then identify the source of the intrusion, address the vulnerabilities that were exploited and strengthen security measures.