Deakin University SIT704: Basic Linux Security - Practical Assignment

This assignment solution details a practical exercise in basic Linux security using the Deakin University server and PuTTY. The task involves logging into the server via SSH, executing commands to check user and group permissions, and analyzing file access rights. The solution includes screenshots demonstrating the process of connecting to the server, running the 'id' command to view user information, and examining the contents of the /etc/passwd file. The assignment explores concepts like root access, group identifiers (GID), and the use of commands such as 'ls -l' and 'grep' to understand file permissions and user privileges within the Linux environment. The reflections highlight the practical application of Linux commands and the importance of understanding user and file permissions for system security.

BASIC LINUX SECURITY

 We are accessing the university server through putty. It is an open-source serial console
that is used to connect remote computers through the protocol.
 We have launch putty in our operating system.
 After the pop-up screen, we need to give the hostname in the session category and we
need to mention the port number so that it may go and connect to the respective server.
 In our experiment, we are given with the hostname interactive.deakin.edu.au and the port
number is 22 .this port number is used to access a Unix file though SSH.
 The next step is to log in to the user with the username and the password. This will open
a home directory in the Linux file system.
Screenshot 1:

Screenshot 2:
Screenshot 3:

Screenshot 4:
Screenshot 5:

Screenshot 6:
Screenshot 7

Reflections
Linux is the operating system that is widely used as an open-source in many organizations. In
this report, Deakin’s Linux server is used to provide a basic understanding of Linux. Putty is
used to performing all the functions. In this task, a username and password are used to login to
the server. We have several commands to check the permission which is allocated to the group
and users in the server. If we want to check more details we can use the command ls –l to list all
the information. The root is used to have access to all the permission to the files like read, write
and execute the file in each directory. The following are the answer to the questions that are
asked (Love 2013) (Schallner 2006):
1) If the GID of the group is set to 0 then it is set to be root Group. The root group has a general-
purpose where a file has to be owned by a user and a group “root” gives the indication for a
default group for the users who own the file. So in the example, the Group is set to have root
access. The screenshot proves id Zoidberg and id afalah will be given read, write and execute
access.
2) When we are executing ls – l /etc/passwd we can see the output from the Screenshot. If we
give,'r' operation means user-level permission is granted. If we use the cat command to find the
list of content in the passwd file then the contents in the file are
 root:x:0:0:root:/root:/bin/bash
 bin:x:1:1:bin:/bin:/sbin/nologin
 daemon:x:2:2:daemon:/sbin:/sbin/nologin
 X represents the file is executable
 It has all the password which is encrypted and stored in etc/shadow file
3) When Grep was used to find the group which begins with '+' no such Group existed. The
Group is set to have user permissions.

REFERENCES
Love, R., 2013. Linux system programming: talking directly to the kernel and C library. "
O'Reilly Media, Inc.".
Schallner, M., 2006. Beginners guide to basic linux anti anti debugging techniques. Code
Breakers Magazine, 1.