A cyber intrusion is an unauthorized or malicious access to a computer system or network by an attacker. A cyber intrusion can compromise the confidentiality, integrity, or availability of the system or network, as well as the data and services that it hosts. A cyber intrusion can also cause damage, disruption, or theft to the organization or its stakeholders. One of the best ways toprevent cyber intrusion is to strengthen vulnerability remediation efforts, which means to identify and fix the weaknesses or flaws in the system or network that can be exploited by the attackers. Vulnerability remediation efforts can include conducting regularvulnerability assessments, applying security patches and updates, configuring security settings and policies, and implementing security controls and measures. By strengthening vulnerability remediation efforts, the organization can reduce the attack surface and the likelihood of cyber intrusion, as well as enhance the resilience and protection of the system or network. The other options are not the best recommendations for preventing cyber intrusion, although they may be helpful and complementary. Establishing a cyber response plan is a technique to prepare for and respond to a cyber incident, such as a cyber intrusion, by defining the roles, responsibilities, procedures, and resources that are needed to manage and recover from the incident. However, a cyber response plan is a reactive and contingency measure, while strengthening vulnerability remediation efforts is a proactive and preventive measure. Implementing data loss prevention (DLP) tools is a technology that tries to detect and stop sensitive data breaches, or data leakage incidents, in an organization. DLP tools can help to protect the data from being disclosed to an unauthorized person, whether it is deliberate or accidental. However, DLP tools do not prevent cyber intrusion itself, as they only focus on the data, not the system or network. Implementing network segregation is a method to divide a network into smaller segments or subnetworks, each with its own security policies and controls. Network segregation can help to isolate and contain the impact of a cyber intrusion, as well as to limit the access and movement of the attackers within the network. However, network segregation does not prevent cyber intrusion from occurring, as it does not address thevulnerabilities or flaws in the system or network. References = CRISC Review Manual, pages 164-1651; CRISC Review Questions, Answers & Explanations Manual, page 902; What Are Security Controls? - F53; Assessing Security Controls: Keystone of the Risk Management … - ISACA4