Vulnerability Monitoring and Scanning

Due to the complexity of modern software, systems, and other factors, new vulnerabilities are discovered on a regular basis. It is important that newly discovered vulnerabilities are added to the list of vulnerabilities to be scanned to ensure that the organization can take steps to mitigate those vulnerabilities in a timely manner.

The breadth of vulnerability scanning coverage can be expressed as a percentage of components within the system, by the particular types of systems, by the criticality of systems, or by the number of vulnerabilities to be checked. Conversely, the depth of vulnerability scanning coverage can be expressed as the level of the system design that the organization intends to monitor (e.g., component, module, subsystem, element). Organizations can determine the sufficiency of vulnerability scanning coverage with regard to its risk tolerance and other factors. Scanning tools and how the tools are configured may affect the depth and coverage. Multiple scanning tools may be needed to achieve the desired depth and coverage. SP 800-53A provides additional information on the breadth and depth of coverage.

Discoverable information includes information that adversaries could obtain without compromising or breaching the system, such as by collecting information that the system is exposing or by conducting extensive web searches. Corrective actions include notifying appropriate organizational personnel, removing designated information, or changing the system to make the designated information less relevant or attractive to adversaries. This enhancement excludes intentionally discoverable information that may be part of a decoy capability (e.g., honeypots, honeynets, or deception nets) deployed by the organization.

In certain situations, the nature of the vulnerability scanning may be more intrusive, or the system component that is the subject of the scanning may contain classified or controlled unclassified information, such as personally identifiable information. Privileged access authorization to selected system components facilitates more thorough vulnerability scanning and protects the sensitive nature of such scanning.

Using automated mechanisms to analyze multiple vulnerability scans over time can help determine trends in system vulnerabilities and identify patterns of attack.

Reviewing historic audit logs to determine if a recently detected vulnerability in a system has been previously exploited by an adversary can provide important information for forensic analyses. Such analyses can help identify, for example, the extent of a previous intrusion, the trade craft employed during the attack, organizational information exfiltrated or modified, mission or business capabilities affected, and the duration of the attack.

An attack vector is a path or means by which an adversary can gain access to a system in order to deliver malicious code or exfiltrate information. Organizations can use attack trees to show how hostile activities by adversaries interact and combine to produce adverse impacts or negative consequences to systems and organizations. Such information, together with correlated data from vulnerability scanning tools, can provide greater clarity regarding multi-vulnerability and multi-hop attack vectors. The correlation of vulnerability scanning information is especially important when organizations are transitioning from older technologies to newer technologies (e.g., transitioning from IPv4 to IPv6 network protocols). During such transitions, some system components may inadvertently be unmanaged and create opportunities for adversary exploitation.

The reporting channel is publicly discoverable and contains clear language authorizing good-faith research and the disclosure of vulnerabilities to the organization. The organization does not condition its authorization on an expectation of indefinite non-disclosure to the public by the reporting entity but may request a specific time period to properly remediate the vulnerability.