Deakin University SIT182 - Unix/Linux Access Control Task Solution

This document provides a comprehensive solution to a Cyber Security assignment, focusing on Unix/Linux Access Control. The assignment covers key concepts such as Docker Engine and its role in application development and isolation through OS-level virtualization. It delves into the kernel's function within an operating system, explaining its role in managing hardware, memory, and tasks. The solution includes practical examples of the `chmod` command and its use in modifying file permissions. Furthermore, it addresses Access Control Lists (ACLs), SUID permissions, and file ownership, offering detailed explanations and answering related interview questions. The assignment also explores security policy, confidentiality, and integrity policies, including the Bell-LaPadula model. Finally, it covers the initial setup and basic traffic analysis using Kali Linux, including installing the VM, using the terminal, and capturing login information using Wireshark. The solution also provides answers to questions about Kali Linux's history and packet analysis techniques.

SIT182 - Real World Practices for Cyber Security
[Name]
Institution

1. Docker Engine
A. Docker Engine is a platform which acts like a client-server system; facilitating the
development and running of applications. The platform helps in separating applications
from the underlying infrastructure through OS-level virtualization; forming a container
that offers security and isolation.
B. The zip file had dockerfile for labsec2, which required to be built in order to run on the
docker
C. `build’ the docker image: The command builds images of Docker from a given
Dockerfile and context files. After building, the resulting docker image can run in a
containerized environment on the docker.
Building labsec2

Successfully built and running
Question 2:
Kernel in an Operating System
This is the core of an operating system, and is always in memory. A kernel is responsible for
managing the overall operations of a computer. In particular, it manages the hardware; CPU
time and memory management as well as disk management and tasks. Code for a given kernel
is securely loaded into a protected memory location.
In some older versions of operating systems, malware can load before Kernel loads. This is
because boot loader runs before the Kernel and can therefore be targeted. For newer versions of
operating systems, it is not possible to load malware before kernel is loaded due to various
security measures.
The password obtained: 44l1c3

Q3
A. `Chmod’ command: this command allows one to set or modify permissions on files and
directories.
B. The Chmod command takes the format: chmod [reference][operator][mode] file
a. The reference part specifies the users who are affected by the permissions they
are specified as; “u” for owner, “g” for group, “o” for other and “a” for all
b. Operator; specifies the adjustments to be done on a file; they include + for add, -
for remove, = for specifying exact modes
c. Modes; they specify the permissions to be granted or revoked on given classes.
The modes include; “r” for read, “W” for write and “x” for execute
C. Command to set permission was;
chmod 754 myfile
Q4): The file Accessible by Carol is file 8. An Access Control Lists (ACLs) was used to
implement fine grained control over the file. By using the keyword getfacl, we see that the carol
can read and write to the file.

Q5)
a. Screenshot of running the commands used in Task 4

b. SUID permission
SUID (Set owner User ID up on execution); this is a type of file permission on executable files,
which allows users to be allowed to execute a file with owner’s rights (Akin, 2001). Ordinarily,
Linux programs runs on inherited access permissions from the active user (Donenfeld, 2011).
With SUID, this approach is changes and any user can run a given file with the highest level of
permissions that’s normally assigned to the owner of the file (O’Leary, 2019). A file with SUID
permission replaces the ordinary execute permission “x” with a special permission indicated by
“s”.
Q6)
A. If you wanted to have a data file that you could read or write, but don't want anyone
else to see, the permission would be -rw- --- ---
B. If the file is owned by the user, the OWNER permission determines the access.
C. If the group of the file is the same as the user's group, the GROUP determines the
access.
D. If the user is not the file owner, and is not in the group, then the OTHER
Q7)
A) “Arash CAN uses the file”. False
B) “Anyone in group GUESTS CANNOT executes the program.” False
C) “Everyone else besides Arash and the members of the GUESTS group can read, write,
and execute the program.” True
Q8). 5 interesting interview questions related to Access Control and Unix Permissions
1. Explain the working of Access control list (ACL) and show how to modify ACL using
setfacl

2. A file named myapp has a mode of 755. If dnelson doesn't own this file and isn't a
member of the group that owns the file, what can she do with it?
3. An executable file has the SUID permission set. If this file is run on the system, who
owns the file?
4. Which special permission can't be assigned to a file?
A. SUID
B. SGID
C. sticky bit
D. None of the above. All special permissions can be assigned to a file.
5. What is Sticky Bit permission?
Questions were obtained from
i. https://www.geeksforgeeks.org/access-control-listsacl-linux/
ii. http://www.gocertify.com/quizzes/linux-practice-questions/linux-file-permissions-quiz.html
iii. https://www.golinuxhub.com/2014/01/interview-questions-on-linux-permissions.html

References
Akin, T., 2001. ‘Dangers of SUID Shell Scripts. Sys Admin Magazine.
Donenfeld, J.A., 2011. Linux local privilege escalation via suid/proc/pid/mem write (2012). URL http://blog.
zx2c4. com/749.
O’Leary, M., 2019. Privilege Escalation in Linux. In Cyber Operations (pp. 419-453). Apress, Berkeley,
CA.