Any person with authorized access to any United States Government resource to include personnel, facilities, information, equipment, networks, or systems.
Source(s):
CNSSI 4009-2015 from CNSSD No. 504

  Any person with authorized access to any U.S. Government resource, to include personnel, facilities, information, equipment, networks, or systems.
Source(s):
NIST SP 800-53 Rev. 4 under Insider from Presidential Memorandum, National Insider Threat Policy and Minimum Standards for Executive Branch Insider Threat Programs

  An entity inside the security perimeter that is authorized to access system resources but uses them in a way not approved by those who granted the authorization.
Source(s):
NIST SP 800-82 Rev. 2 under Insider from RFC 4949
NIST SP 1800-25B under Insider from NIST SP 800-82 Rev. 2, RFC 4949
NIST SP 1800-26B under Insider from NIST SP 800-82 Rev. 2, RFC 4949

  Any person with authorized access to any organizational resource, to include personnel, facilities, information, equipment, networks, or systems.
Source(s):
NIST SP 800-53 Rev. 5 from CNSSI 4009-2015 - Adapted

  Any person with authorized access to business resources, including personnel, facilities, information, equipment, networks, or systems.
Source(s):
NISTIR 7621 Rev. 1 under Insider from CNSSI 4009-2015 - adapted