iSACA Cybersecurity Fundamentals Certification Practice Exam

What characterizes kernel mode in operating systems?

1. Protected execution of user applications

2. Privileged instructions with unrestricted access

3. Low-level network communication

4. Data encryption and decryption

The correct answer is: Privileged instructions with unrestricted access

Kernel mode in operating systems is characterized by privileged instructions with unrestricted access to system resources. When the operating system operates in kernel mode, it has the ability to directly interact with hardware and manage system functions without restrictions imposed on user applications. This level of access allows the operating system to perform critical tasks such as memory management, process scheduling, and hardware communication, which are essential for maintaining the stability and security of the system. In contrast, user applications typically run in user mode, where they face restrictions for security and stability reasons. This separation ensures that user programs cannot directly perform actions that could compromise the system or other processes running on it. By allowing certain instructions and functions to be executed only in kernel mode, the operating system protects itself and the system's integrity from potentially harmful behaviors arising from user applications. Other options, while relating to operating systems, do not accurately describe the characteristics of kernel mode. For instance, protected execution of user applications pertains more to user mode operations. Low-level network communication and data encryption/decryption involve specific operations that can take place in various modes but do not define the primary characteristic of kernel mode itself.