Information System Security Officer (ISSO)

Individual with assigned responsibility for maintaining the appropriate operational security posture for an information system or program. SOURCE: SP 800-37; SP 800-53

Individual assigned responsibility by the senior agency information security officer, authorizing official, management official, or information system owner for maintaining the appropriate operational security posture for an information system or program.
SOURCE: SP 800-53A; SP 800-60

Individual assigned responsibility by the senior agency information security officer, authorizing official, management official, or information system owner for ensuring that the appropriate operational security posture is maintained for an information system or program.
SOURCE: SP 800-18