Overview

Security Requirements for 03.01.05 Least Privilege

Organizations employ the principle of least privilege for specific duties and authorized accesses for users and processes. The principle of least privilege is applied with the goal of authorized privileges no higher than necessary to accomplish required organizational missions or business functions. Organizations consider the creation of additional processes, roles, and system accounts as necessary, to achieve least privilege. Organizations also apply least privilege to the development, implementation, and operation of organizational systems. Security functions include establishing system accounts, setting events to be logged, setting intrusion detection parameters, and configuring access authorizations (i.e., permissions, privileges).Privileged accounts, including super user accounts, are typically described as system administrator for various types of commercial off-the-shelf operating systems. Restricting privileged accounts to specific personnel or roles prevents day-to-day users from having access to privileged information or functions. Organizations may differentiate in the application of this requirement between allowed privileges for local accounts and for domain accounts provided organizations retain the ability to control system configurations for key security parameters and as otherwise necessary to sufficiently mitigate risk.

Assessment GuidanceExamine 0/17

How an assessor determines this requirement is met. Source: CMMC Assessment Guide – Level 2, Version 2.13 (NIST SP 800-171 Rev. 2).

Discussion

The principle of least privilege applies to all users and processes on all systems, but it is critical to systems containing or accessing CUI. Least privilege:

restricts user access to only the machines and information needed to fulfill job responsibilities; and

limits what system configuration settings users can change, only allowing individuals with a business need to change them.

Examples

  1. Example 1

    You create accounts for an organization that processes CUI. By default, everyone is assigned a basic user role, which prevents a user from modifying system configurations. Privileged access is only assigned to users and processes that require it to carry out job functions, such as IT staff, and is very selectively granted [b, d].

Assessment Methods

Examine
The process of reviewing, inspecting, observing, studying, or analyzing assessment objects (e.g., policies, procedures, plans, system designs, mechanisms) to facilitate understanding, achieve clarification, or obtain evidence.Example: An assessor reads the access control policy and inspects system configuration settings to confirm they match.

Not all of the evidence listed is required to meet this requirement — check the items your organization has collected.

Interview
The process of holding discussions with individuals or groups within an organization to facilitate understanding, achieve clarification, or identify the location of evidence.Example: An assessor asks a system administrator to describe how user accounts are approved, reviewed, and disabled.
  • Personnel with account management responsibilities
  • System or network administrators
  • Personnel with information security responsibilities
  • Personnel with responsibilities for defining least privileges necessary to accomplish specified tasks
Test
The process of exercising assessment objects (e.g., activities, mechanisms) under specified conditions to compare actual behavior with expected behavior.Example: An assessor attempts to sign in with a disabled account to confirm that access is denied.
  • Organizational processes for managing system accounts
  • Mechanisms for implementing account management
  • Mechanisms implementing least privilege functions
  • Mechanisms prohibiting privileged access to the system

Potential Assessment Considerations

  • Are privileged accounts documented and is when they may be used defined [a]?
  • Are users assigned privileged accounts to perform their job functions only when it is necessary [b]?
  • Are necessary security functions identified (e.g., access control configuration, system configuration settings, or privileged account lists) that must be managed through the use of privileged accounts [c]?
  • Is access to privileged functions and security information restricted to authorized employees [d]?

Key References

NIST SP 800-171 Rev. 2 3.1.5

Evidence

  1. 03.01.05.a

    Privileged accounts are identified

  1. 03.01.05.b

    Access to privileged accounts is authorized in accordance with the principle of least privilege

  1. 03.01.05.c

    Security functions are identified

  1. 03.01.05.d

    Access to security functions is authorized in accordance with the principle of least privilege