Task 8: Working with Binary and Octal Numbering

In this task you are going to apply your skills in binary and octal numbering to configure *ux directory and file permissions. As a security professional, you need to understand different numbering systems. For example, if youre hardening a Linux system, your understanding of binary helps you create the correct permissions. UNIX uses base-8 (octal) numbering for creating directory and file permissions.

1. Write the octal equivalents for the following binary numbers: 100, 111, 101, 011, and 010

2. Write how to express *nix owner permissions of r-x in binary. (Remember that the symbol means the permissions isnt granted.) whats the octal representation of the binary number you calculated? (the range of numbers expressed in octal is 0 to 7. Because *nix has three sets of permissions, three sets of 3 binary bits logically represent all possible permissions)

3. In binary and octal numbering, how do you express granting read, write, and execute permission to the owner of a file and no permissions to anyone else?

4. In binary and octal numbering, how do you express granting read, write, and execute permission to the owner of a file, read and write permission to group, and read permission to other?

Reflection 3:

Read the below scenario and answer the questions below:

A while back, the IT Help Desk received a number of complaints that one of the employees computers was sending out spam emails. They checked it out, and the reports were true: a hacker had installed a program on the computer that made it automatically send out tons of spam emails without the computer owners knowledge.

1. How do you think the hacker got into the computer to set this up?
2. What security countermeasures would you suggest to prevent this to happen in the future?