Computer System Security 5th Week Solution 2020 || css quiz 5 solution || css quiz solution

Computer System Security 5th Week Solution 2020. 

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Q:1. Chroot jail is used to _______ process and its children by ________ to the supplied directory name.

(a).isolate, changing the root directory

(b).change, the name

(c).execute, renaming it

(d).All of the above

Answer:- (b).change, the name

Reason :- A chroot on Unix operating systems is an operation that changes the apparent root directory for the current running process and its children. The programs that run in this modified environment cannot access the files outside the designated directory tree. This essentially limits their access to a directory tree and thus they get the name “chroot jail”.

Q:2. Taliking about FreeBSD jail, which of the following is true ?

(a).It can only bind to sockets with specified IP address and authorized ports

(b).It can communicate with processes inside and outside of jail

(c).Root is limited (example: cannot load kernel modules)

(d).None of the above

Answer :-(b).It can communicate with processes inside and outside of jail

Reason :- The jail mechanism is an implementation of FreeBSD's OS-level virtualisation that allows system administrators to partition a FreeBSD-derived computer system into several independent mini-systems called jails, all sharing the same kernel, with very little overhead.

Q:3. Which of the following is incorrect for System call interposition?

(a).It tracks all the system service requests of processes.

(b).Each system request can be modified or denied.

(c).It is impossible to implement tools to trace, monitor, or virtualize processes.

(d).None of the above.

Answer:-(c).It is impossible to implement tools to trace, monitor, or virtualize processes.

Reason:- Abstract: System call interposition is a powerful method for regulating and monitoring program behavior. ... A system call correlating method is proposed to identify the coherent system calls belonging to the same process from the system call sequence. 

Q:4. Which of the following is a computer security utility which limits an application's access to the system by enforcing access policies for system calls?

(a).systrace

(b).NetBSD

(c).ptrace

(d).None of the above

Answer:- (a).systrace

Reason:- Systrace is a computer security utility which limits an application's access to the system by enforcing access policies for system calls. This can mitigate the effects of buffer overflows and other security vulnerabilities.

Q:5. Which of the following uses a call back mechanism in the kernel module to redirect system calls?

(a).systrace

(b).ptrace

(c).ostia

(d).NetBSD

Answer :- (b).ptrace

Reason:- ptrace is a system call found in Unix and several Unix-like operating systems. By using ptrace (the name is an abbreviation of "process trace") one process can control another, enabling the controller to inspect and manipulate the internal state of its target.