Hacktivists are hackers who use their skills to promote a political or social cause, such as human rights, environmentalism, anti-censorship, etc. Hacktivists may target organizations or individuals who oppose their views or agendas, and launch cyberattacks such as defacement, denial-of-service, data theft, or sabotage. In this case, the security manager should consider hacktivists as a potential threat actor who may launch cyberattacks in response to the CEO's controversial opinion article.

Explanation
Heuristic analysis is also one of the few methods capable of combating polymorphic viruses - the term for malicious code that constantly changes and adapts. Heuristic analysis is incorporated into advanced security solutions offered by companies like Kaspersky Labs to detect new threats before they cause harm, without the need for a specific signature. https://usa.kaspersky.com/resource-center/definitions/heuristic-analysis

Explanation
DNS spoofing, also referred to as DNS cache poisoning, is a form of computer security hacking in which corrupt Domain Name System data is introduced into the DNS resolver's cache, causing the name server to return an incorrect result record, e.g. an IP address. This results in traffic being diverted to the attacker's computer (or any other computer). https://en.wikipedia.org/wiki/DNS_spoofing

A host-based firewall is a software application that runs on each individual host and controls the incoming and outgoing network traffic based on a set of rules. A host-based firewall can be used to block or allow specific ports, protocols, IP addresses, or applications.
An engineer can use a host-based firewall to accomplish the task of disabling all web-server ports except 443 on a group of 100 web servers in a cloud environment. The engineer can configure the firewall rules on each web server to allow only HTTPS traffic on port 443 and deny any other traffic. Alternatively, the engineer can use a centralized management tool to deploy and enforce the firewall rules across all web servers.