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Access Control

Updated Jan 30, 2024 ·

Security Control​

A control is a protective measure aiming to uphold the principles of Confidentiality, Integrity, and Availability (CIA Triad) for data.

Access control, a subset, dictates the availability of objects to subjects based on specific rules.

For instance, a firewall is a control implemented in systems or networks to prevent external threats from compromising the environment and restrict unauthorized access to information within.

Elements of Access Control​

Access controls involve more than just limiting access; they also encompass facilitating appropriate access for authorized personnel and processes while blocking access for unauthorized functions or individuals.

Subjects​

Subjects are the active initiators of service requests.

  • Types: Users, processes, clients, programs, devices (endpoints, smartphones, etc.).
  • Actively initiate access requests to resources or services.
  • Request services from objects.
  • Require suitable clearance (permissions) for accessing services or resources.

Objects​

By definition, anything that a subject attempts to access is referred to as an object.

  • Types: Buildings, computers, files, databases, printers, servers, memory blocks, etc.
  • Passive responders to subject-initiated service requests.
  • Lack their own access control logic, relying on integrated systems.
  • Access is often recorded in rule bases or access control lists.
  • May be classified based on access rules.

Rules​

Access rules guide whether a subject can access an object based on their validated identity. For instance:

  • Firewalls use access control lists for object access.
  • Rules specify access levels, e.g., inside network to outside.
  • When a user accesses a file, a rule validates and defines their access.
  • Rules may compare attributes, define access levels, deny access, or apply time-based restrictions.

Location-Based Access Control​

Geolocation is the process of determining where a user or device is located using IP address, GPS, or network data. It's commonly used in cybersecurity to help control access and detect suspicious activity.

  • Enables tracking the physical location of devices
  • Useful for finding lost or stolen devices wipe them remotely.

Geolocation can be applied in several ways:

  • Geofencing

    • Restricts access or device use based on physical location
    • Often used to block access outside office zones or specific countries

  • Geotagging

    • Adds location metadata to files, photos, or logs
    • Useful for tracking data movement or detecting unusual file activity

  • Impossible Travel

    • Flags suspicious logins from distant locations within a short time
    • Note that this can be bypassed using VPN or Tor

Controls Assessment​

Risk reduction relies on the control's efficacy, adapting to changing situations. As an example, in securing a repurposed office space for confidential file storage, consider the following:

  • Evaluate the necessity of biometric scanners on all doors.
  • Conduct a site assessment to determine optimal scanner placement.
  • Consider permanently securing or replacing non-critical doors.
  • Ensure control implementation aligns with the value of the protected assets.

There are many ways organizations can evaluate their control's effectiveness:

  • Track the number of compromised end-user accounts.
  • Track number of detected vulnerabilities.
  • Monitor critical findings in initial web scans.
  • Track number of data breaches requiring notifications.

Privileged Access Management​

To ensure confidentiality, integrity, and availability of information, the Principle of Least Privilege is employed through Privileged Acces ,Management. Users receive access only to essential items, limiting exposure.

For more information, please see PAM.