| In order to prevent unauthorized connection of devices, unauthorized transfer of information, or unauthorized tunneling (i.e., embedding of data types within data types), organizations must disable or restrict unused or unnecessary physical and logical ports/protocols on information systems.
Operating systems are capable of providing a wide variety of functions and services. Some of the functions and services provided by default may not be necessary to support essential organizational operations. Additionally, it is sometimes convenient to provide multiple services from a single component (e.g., VPN and IPS); however, doing so increases risk over limiting the services provided by any one component.
To support the requirements and principles of least functionality, the operating system must support the organizational requirements, providing only essential capabilities and limiting the use of ports, protocols, and/or services to only those required, authorized, and approved to conduct official business or to address authorized quality of life issues.
Several user exit points in the FTP Server component are available to permit customization of its operating behavior. These exits can be used to modify functions such as FTP command usage, client connection controls, post processing tasks, and SMF record modifications. Without proper review and adequate documentation of these exit programs, undesirable operations and degraded security may result. This exposure could lead to unauthorized access impacting data integrity or the availability of some system services, or contribute to the loss of accountability and hamper security audit activities. |