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Cyber Security Framework (CSF)

NIST Cyber Security Framework

The NIST CSF was designed with the intent that individual businesses and other organisations use an assessment of the business risks they face to guide their use of the framework in a cost-effective way.

The framework is divided into three parts: the Framework Core, Framework Implementation Tiers and Framework Profiles:

  • The Framework Core is a set of activities, outcomes and references that detail approaches to aspects of cyber security. The core comprises five functions, which are subdivided into 22 categories (groups of cyber security outcomes) and 98 subcategories (security controls).
  • Framework Implementation Tiers are used by an organisation to clarify for itself and its partners how it views cyber security risk and the degree of sophistication of its management approach.
  • A Framework Profile is a list of outcomes that an organisation has chosen from the categories and subcategories, based on its business needs and individual risk assessments.

Core framework functions

The core functions are:

  • Identify – Develop the organisational understanding to manage cyber security risk to systems, assets, data and capabilities.
  • Protect – Develop and implement the appropriate safeguards to ensure delivery of critical infrastructure services.
  • Detect – Develop and implement the appropriate activities to identify the occurrence of a cyber security event.
  • Respond – Develop and implement the appropriate activities to take action regarding a detected cyber security event.
  • Recover – Develop and implement the appropriate activities to maintain plans for resilience and to restore any capabilities or services that were impaired because of a cyber security event.

Each function is divided into categories – groups of cyber security outcomes that relate to particular activities. Examples include ‘Asset Management’, ‘Access Control’ and ‘Detection Processes’.

Subcategories further divide a category into specific outcomes of technical and/or management activities (security controls). Examples include ‘External information systems are catalogued’, ‘Data-at-rest is protected’ and ‘Notifications from detection systems are investigated’.

For each subcategory, the CSF provides informative resources that cite specific sections of a variety of information security standards, including ISO 27001, COBIT®, NIST SP 800-53, ISA 62443, and the Center for Internet Security's 20 Critical Security Controls.

Helping you implement the framework

An organisation typically starts by using the framework to develop a profile that describes its current cyber security activities and their outcomes. It can then develop a target profile, or adopt a baseline profile that has been tailored to better match its critical infrastructure sector or the type of organisation. Steps can then be taken to close the gaps between its current profile and its target profile.

The following seven steps are used to create a new cyber security programme or improve an existing one. These steps should be repeated as necessary to continually improve and assess your cyber security:

  • Step 1: Prioritise and scope
  • Step 2: Orient
  • Step 3: Create a current profile
  • Step 4: Conduct a risk assessment
  • Step 5: Create a target profile
  • Step 6: Determine, analyse and prioritise gaps
  • Step 7: Implement action plan

Although there is no mandatory, legal or regulatory requirement that stipulates that organisations must implement the CSF, some organisations do have contractual requirements passed down to them from their clients and suppliers to use and implement the CSF.