CISSP Exam 2025 – 400 Free Practice Questions to Pass the Exam

The purpose of a blacklist in cybersecurity is to maintain a set of known bad resources such as IP addresses, domain names, or applications that have been identified as malicious or harmful. Blacklists are crucial for implementing security measures, as they help organizations prevent access to these harmful resources. By using blacklists, security systems can filter out or block traffic, effectively reducing the chances of attacks or breaches.

In many security contexts, blacklists are used in conjunction with other security measures, such as firewalls and intrusion detection systems, to enhance the overall security posture. For example, if a specific IP address has been associated with known cybercriminal activity, it can be added to a blacklist. Systems that reference this blacklist will deny any incoming or outgoing traffic to or from that IP address, thereby helping protect the organization's network and assets.

The other options reflect concepts that don't align with the fundamental purpose of a blacklist. For instance, a recommended software applications list focuses on safe and trusted applications, while a historical record of previous incidents deals with learning from past breaches. A collection of authorized users pertains to access control rather than identifying threats. This distinction is essential for understanding the different roles various lists play in a comprehensive cybersecurity strategy.