3.13.7Block split tunneling in Rev. 3

Remote access is access to systems (or processes acting on behalf of users) that communicate through external networks, such as the internet. Monitoring and controlling remote access methods allows organizations to detect attacks and ensure compliance with remote access policies. Routing remote access through managed access control points enhances explicit control over such connections and reduces susceptibility to unauthorized access to the system, which could result in the unauthorized disclosure of CUI. Remote access to the system represents a significant potential vulnerability that can be exploited by adversaries. Restricting the execution of privileged commands and access to security-relevant information via remote access reduces the exposure of the organization and its susceptibility to threats by adversaries. A privileged command is a human-initiated command executed on a system that involves the control, monitoring, or administration of the system, including security functions and security-relevant information. Security-relevant information is information that can potentially impact the operation of security functions or the provision of security services in a manner that could result in failure to enforce the system security policy or maintain isolation of code and data. Privileged commands give individuals the ability to execute sensitive, security-critical, or security-relevant system functions.

Configuration settings are the set of parameters that can be changed in hardware, software, or firmware components of the system and that affect the security posture or functionality of the system. Security-related configuration settings can be defined for systems (e.g., servers, workstations), input and output devices (e.g., scanners, copiers, printers), network components (e.g., firewalls, routers, gateways, voice and data switches, wireless access points, network appliances, sensors), operating systems, middleware, and applications. Security parameters are those parameters that impact the security state of the system, including the parameters required to satisfy other security requirements. Security parameters include registry settings; account, file, and directory permission settings (i.e., privileges); and settings for functions, ports, protocols, and remote connections. Organizations establish organization-wide configuration settings and subsequently derive specific configuration settings for the system. The established settings become part of the system’s configuration baseline. Common secure configurations (also referred to as security configuration checklists, lockdown and hardening guides, security reference guides, and security technical implementation guides) provide recognized, standardized, and established benchmarks that stipulate secure configuration settings for specific information technology platforms/products and instructions for configuring those system components to meet operational requirements. Common secure configurations can be developed by a variety of organizations, including information technology product developers, manufacturers, vendors, consortia, academia, industry, federal agencies, and other organizations in the public and private sectors.

Systems can provide a variety of functions and services. Some functions and services that are routinely provided by default may not be necessary to support essential organizational missions, functions, or operations. It may be convenient to provide multiple services from single system components. However, doing so increases risk over limiting the services provided by any one component. Where feasible, organizations limit functionality to a single function per component. Organizations review the functions and services provided by the system or system components to determine which functions and services are candidates for elimination. Organizations disable unused or unnecessary physical and logical ports and protocols to prevent the unauthorized connection of devices, the transfer of information, and tunneling. Organizations can employ network scanning tools, intrusion detection and prevention systems, and endpoint protection systems (e.g., firewalls and host-based intrusion detection systems) to identify and prevent the use of prohibited functions, ports, protocols, system connections, and services. Bluetooth, File Transfer Protocol (FTP), and peer-to-peer networking are examples of the types of protocols that organizations consider eliminating, restricting, or disabling.