UNIX question

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1. We consider that we are running on a UNIX system which uses ACL as a mechanism for file protection. Where is the protection information of the file stored?

2. In UNIX, each device is represented by a device, give an example of a file representing the hard disk storage device. Give the full listing of this file using the "ls -l" command. What are the protection flags (rwx) for this file and WHY are they like this? What would happen if the protection flags were equal to rw-rw-rw ?

3. What is the definition of MAC Times for UNIX systems? provide an example about the difference between the M flag and C flag.

4. A system administrator suspects that there is an attack on his machine; he needs to make a backup of the files to check when they have been modified. For this purpose he uses the "cp –r" instruction to copy the root directory. What is the problem with this and what other instruction should the administrator use in order to avoid this problem?

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1. What is a "two-factor" authentication?
2. Provide a full example of two-factor authentication where one factor is a password.
3. Could we use the mobile phone as part of this two-factor authentication?
4. Is "google" authentication a two-factor authentication system? What is the main problem with this device?


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