In the context of OS security, what does the term "layered defense" imply?

Layered defense is an essential concept in operating system security, referring to the implementation of multiple security measures across different layers or levels of a system. This strategy ensures that if one security measure fails, others remain in place to protect the system. By employing a variety of defenses—such as firewalls, intrusion detection systems, antivirus software, and physical security techniques—organizations can create a more robust security posture.

Each layer addresses specific types of threats and vulnerabilities, thus providing redundancy and increasing the chances of thwarting malicious attempts. For example, while a firewall may block unauthorized access, antivirus software can prevent malware from executing. This approach enhances overall security as it does not rely on a single point of failure.

In contrast, using a single type of security tool would make the system vulnerable if that tool is compromised. Focusing solely on software security ignores the physical and operational dimensions that can also impact system integrity. Reliance solely on user vigilance, while important, is insufficient since human factors can be unpredictable and often lead to security lapses. Thus, a layered defense strategy offers a comprehensive and effective means of protecting operating system security.