Introduction to the NIS Directive

The NIS Directive is one major cyber security regulation for the services we use in our daily lives. This white paper is the first of a series that explores the NIS Directive and how it shall strengthen our society against cyber attacks.


The Directive on security of network and information systems (NIS Directive) is one major cyber security regulation in these recent years. The objective of the NIS Directive is to strengthen the protection of the services we use in our daily lives against cyber attacks. This includes Operators of Essential Services (including several Critical National Infrastructure operators) and Digital Service Providers.

In this article, we will learn more about the NIS Directive, the scope of application and its obligations. More articles will follow in this series to better apprehend this directive.

Why the NIS Directive?

The convergence to IP-connected systems is here. We live in a connected world and use interdependent cyber-physical systems every day. These cyber-physical systems rely on software and networks to provide a service in the physical world. To add to this complexity, human operators use computer systems for remote command/control these systems.

Cyber-physical systems face several security risks: vendors and integrators are not security experts. Moreover, several cyber-physical systems are “legacy systems” that were designed before IP-connectivity. They were not meant to be connected and may not be supported by their vendors.

Yet, connectivity brings very interesting functionalities to optimise operations and maintenance, leading these systems to become interdependent. As such, they also face traditional cyber security risks such as malware, ransomware or Denial of Service.

Hence, cyber security is important to prevent issues that could impede safety, our economy or our society. For all these reasons, the NIS Directive was created to better prepare against these cyber risks.

The consequences of a cyber attack

Since Wannacry happened in May 2017, nobody will argue that our society is safe from cyber attacks. In the United Kingdom, the National Health Service was severely impacted and thousands of patients have seen their appointment cancelled. In Germany, train stations and passenger information systems malfunctioned. Yet, it was very lucky that Wannacry did not cause any casualty!

Wannacry was a wake-up call for several organisations that were hit by this ransomware: they were not a target and this was far from a sophisticated attack (it was easy to remediate even when patching was impossible).

Before and since then, several other attacks have been happening, with similar impacts but barely the same degree of visibility in the media. These cyber attacks cause direct damage to our society, with service disruption and data loss that could impede our privacy. They also lead to organisational risks with users losing trust in the organisations hit, as well as potential breaches in regulation. Moreover, some cyber attacks have significant consequences on our society, with an economic impact and potential human casualties.

The NIS Directive or the “GDPR of Critical Infrastructure”

The NIS Directive is a European Union Directive, meaning “a legal act of the European Union which requires member states to achieve a particular result without dictating the means of achieving that result”. As such, the NIS Directive requires a local implementation by its 27 Member States as well as in the United Kingdom under the name “NIS Regulations”.

The NIS Directive formalises the requirements for the security of network and information systems to enhance the protection against incidents that could disrupt systems or data contributing to a service.

Developed at the same time as GDPR, the NIS Directive goes beyond the security of private data. It focuses on availability, authenticity and integrity as well as confidentiality. The NIS Directive is in force since May 2018. Yet some EU Member States are still in the process of finalising their implementation.

Since the objective of the NIS Directive is to protect domains important to the society from cyber attacks, the sectors in scope have been chosen with care. Most of these sectors are interdependent and critical to the good function of our society: a cyber incident in one sector can trigger consequences onto other sectors.

Figure 1. Sectors in Scope of the NIS Directive

The NIS Directive distinguishes two types of organisations:

The NIS Directive also contains obligations for Member States, that must define regulatory roles (Competent Authorities), and a national CSIRT to support organisations in terms of preparedness and incident response. Member States must also contribute at EU-level via the NIS Cooperation Group and share information on a regular basis via yearly and bi-yearly reports.

For more information, please refer to the “Directive (EU) 2016/1148 of the European Parliament and of the Council of 6 July 2016 concerning measures for a high common level of security of network and information systems across the Union”.

Security requirements in the NIS Directive

The NIS Directive sets up security requirements for OESs and DSPs. While the intention is to establish a security baseline across the European Union, the NIS Directive only establishes high-level requirements. The NIS Directive does not prescribe any specific approach and Member States have adapted these requirements in their local implementation in line with their existing mechanisms, local culture, etc.

Security Measures for Operators of Essential Services

The NIS Directive specifies the following:

Operators of essential services take appropriate and proportionate technical and organisational measures to manage the risks posed to the security of network and information systems which they use in their operations. Having regard to the state of the art, those measures shall ensure a level of security of network and information systems appropriate to the risk posed.

The words “appropriate and proportionate” are the two very important keywords in the NIS Directive. It means that OES must demonstrate that their security measures are appropriate to remediate the risks they face. These security measures must also be proportionate to the risk: they are implemented promptly, without causing a damageable impact on the business, its finance, organisation, or ability to operate.

The NIS Directive requires security measures to go beyond their technical aspect, by requiring an organisational approach. This means that OES will have to identify their security objectives by taking into account people and processes on top of technologies. For instance, some OES will they need to define a governance around security, identify their critical assets, the risks they face, their staff, as well as a continuous improvement process. These requirements go way beyond IT systems: they cover OT (Operational Technologies) and any other network and information system that contributes to the essential service.

Many of times, the NIS Directive will be the occasion to formalise what is already in place. It will also be a great tool to identify gaps and priorities, refine roles and responsibilities and make sure security becomes a topic at board-level.

Security Measures for Digital Service Providers

Similarly, DSPs must take “appropriate and proportionate” security measures to reduce the risks to their services. The NIS Directive requires that they must consider at minimum five specific domains:

“Having regard to the state of the art, those measures shall ensure a level of security of network and information systems appropriate to the risk posed, and shall take into account the following elements:

  1. the security of systems and facilities;
  2. incident handling;
  3. business continuity management;
  4. monitoring, auditing and testing;
  5. compliance with international standards.”

These requirements offer a way for DSPs to capitalise on their existing security investments. For example, several DSPs have already invested to comply with international standards in information security.

Incident Notification

Both OESs and DSPs must notify their competent authority and/or the national CSIRT of any incidents that could disrupt their service. They must notify these incidents without undue delay which gives OESs and DSPs the possibility to reemploy the same mechanisms as in GDPR. Note that the NIS Directive does not specify any time-bound requirement for this notification (some Member States have defined a 72 hours window after detection).

For OESs, each competent authority establishes notification thresholds that define when an incident has a significant impact on the continuity of service. These thresholds can depend on any of the following parameters:

For DSPs, they must notify incidents that have a substantial impact on the provision of service. The competent authority can define such incidents as a combination of:

OESs and DSPs can proceed with a voluntary notification for incidents that are below these thresholds. The intent is to get a better visibility on cyber threats and enhance the security posture within a sector or even at national level.

Enforcement and penalty

In the NIS Directive, the competent authority is the regulator for its sector. It can ensure compliance of its OESs/DSPs with the NIS Directive requirements and assess that their security measures are appropriate and proportionate through audits and inspections. For that purpose, OESs and DSPs need to provide evidence that they implement the requirements of the NIS Directive, and how they do it.

Contrary to other regulations, the intent of the NIS Directive is to follow a cooperative approach to enforcement. The competent authority will exchange with its OESs/DSPs to make sure they understand the requirements of the NIS Directive, assess their risks, know their gaps and establish an improvement roadmap. This stepped approach to regulation shall provide immediate benefits not only to OESs and DSPs, but to the society as a whole.

Nevertheless, competent authorities have the possibility to issue penalties. Penalties can arise in case of a breach of compliance or when the security measures (or lack of) present a risk to the essential service or the society. These penalties shall be effective, proportionate and dissuasive. Each Member State defines its own penalty regime (this could be quite high, with maximum penalties going as high as to £17M in the UK).

In the spirit of the NIS Directive, a competent authority will consider the willingness of an operator to remediate its infringement in order to reduce its penalty. For that purpose, penalties remain the last resort to enforce compliance with the NIS Directive.

The last decade has seen an increase in cyber attacks on critical infrastructure around the world with consequences on the economy and the society. It was only a matter of time before such attacks would affect European Union Member States, as the Internet has no border.

Yet, OES and DSP have shown limited investment in cyber security. This was mostly due to their limited awareness and the fact that they had confidence they were “not a target” (note that Wannacry was not a targeted attack). Yet, should an incident happen, most of these organisations tend to follow a reactive stance which could lead to undesirable effects at large scale.

The intention of the NIS Directive is to palliate this, by highlighting new compliance requirements that bring security to the board’s agenda. This is reinforced by several possible penalties that regulators can adapt to non-compliance, but also to the lack of appropriate and proportionate security measures that may cause an incident on the service.

The dissuasive penalties bring incentives to OESs and DSPs to invest in security instead of accepting the current status-quo and paying a lower fine.


The NIS Directive is an important new piece of regulation. Its objective is to strengthen the security of services essential to our society. It brings new obligations to Operators of Essential Services and Digital Service Providers. They must implement appropriate and proportionate security measures and notify cyber incidents without undue delay.

The NIS Directive requires a new way of thinking. A successful security approach goes beyond technical requirements. It must be endorsed at board-level whilst following a continuous improvement approach. For that purpose, every stakeholder will need to consider their current capabilities and devise improvements towards a stronger collaboration, more proactiveness, and information exchange.

In the next article, we will discuss on methods to identify the scope of the NIS Directive.

About Cetome

Cetome is an independent security consultancy based in London, UK and Lyon, France and operating globally. We work with organisations where security is important and that need to tackle several challenges in terms of resources, capabilities or skills. Most of our clients have an international presence and 250+ staff. At Cetome, we understand the challenges of the NIS Directive its complexity. We work with OESs to help them assess their security posture and implement appropriate and proportionate security measures. Cetome has developed and delivered the only GCHQ Certified Training on the NIS Directive and the Cyber Assessment Framework.

About the Author

Dr. Cédric LÉVY-BENCHETON is the CEO and founder of Cetome. Cédric has expertise in the NIS Directive and OT/ICS security. Cédric previously worked at ENISA, the European Union Cyber Security Agency. Before that, Cédric designed critical networks for public transports.