CIP-005 Electronic Security Perimeter - Host-Based Firewall Rules Report

The North American Electric Reliability Corporation (NERC) is a not-for-profit international regulatory authority whose mission is to assure the reliability of the bulk power system in North America. NERC Reliability Standards define the reliability requirements for planning and operating the North American bulk power system, which serves more than 334 million people. NERC is committed to protecting the bulk power system against cyber security compromises that could lead to misoperation or instability. The NERC Critical Infrastructure Protection (CIP) Standards provide a cyber security framework for the identification and protection of Bulk Electric System (BES) Cyber Systems, to support the reliable operation of the North American bulk power system.

The purpose of CIP-005 (Electronic Security Perimeter(s)) is "to manage electronic access to BES Cyber Systems by specifying a controlled Electronic Security Perimeter in support of protecting BES Cyber Systems against compromise that could lead to misoperation or instability in the BES." A critical aspect of protecting any network is protecting the network perimeter against external infiltration and attacks. In order to accomplish this, boundary protection devices and services such as firewalls, routers, anti-virus, and Intrusion Detection Systems (IDS) should be implemented within each network security perimeter. Proper network segmentation is crucial in the protection of network resources. Applying a multi-layered defense strategy will allow for multiple devices and services to protect the network in case one layer is breached. Attackers will target the weakest link on a network and pivot to other machines. If proper electronic security perimeters and protections are not established, compromise of one relatively unimportant machine can lead to catastrophic damage on critical systems.

For organizations that are required to be CIP compliant, Tenable.sc Continuous View (CV) can lead the way to compliance. CIP-005 requires that access to BES Cyber Systems be controlled. As noted in the standard, one example of evidence for this access control is a list of firewall rules. Regular review of firewall rules is important to ensure that proper access control is being enforced. This report presents the rule sets on all host-based firewalls, as detected by Nessus plugins 56310 (Firewall Rule Enumeration) and 61797 (WMI Firewall Rule Enumeration). This report can assist in monitoring host-based firewall configurations and meeting the CIP-005 access control requirements and measures.

The CIP standards recommend categorizing BES Cyber Assets into different impact categories. An asset's impact category is based on the adverse impact to BES reliability that would occur if the asset was unavailable, degraded, or misused. Once the impact categories of systems have been determined, asset groups in Tenable.sc CV can be used to group together machines in each impact category. Asset groups can then be applied to this report to narrow the focus and enable more accurate reporting on systems in specific impact categories. Using assets with reports is very similar to using assets with dashboards; for more information, see How to Add Assets in SecurityCenter and How to Use Assets with Dashboards. A similar approach can be used to group assets within security perimeters. Alternatively, if the assets are in separate subnets, then subnet filters can be easily applied to narrow the focus of this report.  

This report is available in the Tenable.sc Feed, a comprehensive collection of dashboards, reports, Assurance Report Cards, and assets. The report can be easily located in the Tenable.sc Feed under the category Compliance. The report requirements are:

• SecurityCenter 5.2.0
• Nessus 8.4.0

Tenable.sc Continuous View (CV) is the market-defining continuous network monitoring solution. For Supervisory Control and Data Acquisition (SCADA) systems, where reliability and not interfering with normal operations is a concern, Tenable.sc CV includes passive vulnerability detection with the Nessus Network Monitor (NNM), as well as log correlation with the Log Correlation Engine (LCE). Where possible, active vulnerability detection and compliance scanning with Nessus can also be done. Using Tenable.sc CV, an organization will obtain the most comprehensive and integrated view of its SCADA network.

Chapters

Executive Summary - CIP-005 (Electronic Security Perimeter) requires that access to BES Cyber Systems be controlled. As noted in the standard, one example of evidence for this access control is a list of firewall rules. This chapter presents the hosts from which host-based firewall rule sets were obtained.

Host-Based Firewall Rule Sets - CIP-005 (Electronic Security Perimeter) requires that access to BES Cyber Systems be controlled. As noted in the standard, one example of evidence for this access control is a list of firewall rules. This chapter presents the rule sets on all host-based firewalls. This information can assist an organization in monitoring host-based firewall configurations and meeting the CIP-005 requirements and measures.